Liquid crystal display device and manufacturing method thereof

ABSTRACT

A liquid crystal display device includes a liquid crystal display element including a first alignment film and a second alignment film and a liquid crystal layer that is provided between the first alignment film and the second alignment film, wherein the first alignment film includes a compound in which a polymer compound that includes a cross-linked functional group or a polymerized functional group as a side chain is cross-linked or polymerized, the second alignment film includes the same compound as the compound that configures the first alignment film, and the formation and processing of the second alignment film is different from the formation and processing of the first alignment film and when a pretilt angle of the liquid crystal molecules which is conferred by the first alignment film is θ 1  and a pretilt angle of the liquid crystal molecules which is conferred by the second alignment film is θ 2 , θ 1 &gt;θ 2 .

RELATED APPLICATIONS

This Application claims the benefit under 35 U.S.C. §120 of U.S.application Ser. No. 13/399,271, entitled “LIQUID CRYSTAL DISPLAY DEVICEAND MANUFACTURING METHOD THEREOF” filed on Feb. 17, 2012, which isherein incorporated by reference in its entirety. Foreign prioritybenefits are claimed under 35 U.S.C. §119(a)-(d) or 35 U.S.C. §365(b) ofJapanese application number 2011-040326, filed Feb. 25, 2011.

BACKGROUND

The present disclosure relates to a liquid crystal display device thatincludes a liquid crystal display element in which a liquid crystallayer is sealed between a pair of substrates with alignment films onopposing faces and a manufacturing method of the liquid crystal displaydevice.

In recent years, liquid crystal displays (LCD) have often been used asthe display monitor for liquid crystal television sets, notebookpersonal computers, car navigation devices, and the like. Such liquidcrystal displays are categorized into various display modes (systems)according to the molecular arrangement (alignment) of the liquid crystalmolecules that are contained in the liquid crystal layer that isinterposed between the substrates. As the display mode, for example, aTN (Twisted Nematic) mode in which the liquid crystal molecules aretwisted and aligned in a state in which a voltage is not applied iscommonly used. With the TN mode, the liquid crystal molecules have aproperty in which the positive dielectric constant anisotropy, that is,the dielectric constant of the liquid crystal molecules in the long axisdirection is large compared to the short axis direction. The liquidcrystal molecules therefore have a structure in which the alignmentpositions of the liquid crystal molecules are sequentially rotatedwithin a plane that is parallel to the substrate faces, while beingaligned in a direction that is vertical to the substrate faces.

On the other hand, there has been growing attention on a VA (VerticalAlignment) mode in which the liquid crystal molecules are alignedvertically to the substrate faces in a state in which a voltage is notapplied. With the VA mode, the liquid crystal molecules have a propertyin which the negative dielectric constant anisotropy, that is, thedielectric constant of the liquid crystal molecules in the long axisdirection is small compared to the short axis direction, and a widerviewing angle is able to be realized compared to the TN mode.

Such a VA mode liquid crystal display has a structure in which light istransmitted by the liquid crystal molecules that are aligned in adirection that is vertical to the substrates reacting to a voltage beingapplied by falling to a direction that is parallel to the substrates dueto the negative dielectric constant anisotropy. However, since thedirection in which the liquid crystal molecules that are aligned in thevertical direction with respect to the substrates fall is arbitrary, theresponse characteristics with respect to the voltage may be deterioratedby the alignment of the liquid crystal molecules becoming disturbed bythe application of the voltage.

Accordingly, as an approach to regulating the direction in which theliquid crystal molecules fall in response to the application of thevoltage, a technique of aligning the liquid crystal molecules from adirection that is vertical to the substrates toward a specifieddirection (known as conferring a pretilt) by forming a polymer layerwith a predetermined structure on opposing faces of the substrates hasbeen developed (for example, refer to Japanese Unexamined PatentApplication Publication No. 2002-357830). With such a technique, it ispossible for the direction in which the liquid crystal molecules fallwhen a voltage is applied to be determined in advance, and the responsecharacteristics with respect to the application of the voltage are ableto be improved.

SUMMARY

With such a technique of conferring a pretilt, while it is possible toimprove the startup speed of an image display on the liquid crystaldisplay device, the response speed when the application of the voltageis interrupted is not easily improved. On the other hand, in order tocope with the increase in the number of display frames in the liquidcrystal display device, it is important not only that the startup speedof the image display be improved but also that the termination speed beimproved. Further, if the materials that configure the alignment filmsthat are formed on each substrate of a liquid crystal display deviceconfigured by two substrates are different, as a result of thedifferences in changes to the alignment films over time, there is aconcern that the long-term reliability of the liquid crystal displaydevice is reduced.

It is desirable to provide a liquid crystal display device that is ableto improve the termination speed while avoiding a reduction in long-termreliability, and a manufacturing method thereof.

According to a first embodiment of the present disclosure, there isprovided a liquid crystal display device including: a liquid crystaldisplay element including a first alignment film and a second alignmentfilm that are provided on opposing face sides of a pair of substratesand a liquid crystal layer that is provided between the first alignmentfilm and the second alignment film and that includes liquid crystalmolecules with negative dielectric constant anisotropy, wherein thefirst alignment film includes a compound in which a polymer compoundthat includes a cross-linked functional group or a polymerizedfunctional group as a side chain is cross-linked or polymerized (forconvenience, referred to as “post-alignment process compound”), thesecond alignment film includes the same compound (post-alignment processcompound) as the compound that configures the first alignment film(post-alignment process compound), and the formation and processing ofthe second alignment film is different from the formation and processingof the first alignment film and when a pretilt angle of the liquidcrystal molecules which is conferred by the first alignment film (thatis, by the post-alignment process compound) is θ₁ and a pretilt angle ofthe liquid crystal molecules which is conferred by the second alignmentfilm (that is, by the post-alignment process compound) is θ₂, θ₁>θ₂.Here, “cross-linked functional group” refers to a group that is able toform a cross-linked structure (bridged structure), and morespecifically, refers to dimerization. Further, “polymerized functionalgroup” refers to a functional group in which two or more functionalgroups perform successive polymerization.

According to a second embodiment of the present disclosure, there isprovided a liquid crystal display device including: a liquid crystaldisplay element including a first alignment film and a second alignmentfilm that are provided on opposing face sides of a pair of substratesand a liquid crystal layer that is provided between the first alignmentfilm and the second alignment film and that includes liquid crystalmolecules with negative dielectric constant anisotropy, wherein thefirst alignment film includes a compound in which a polymer compoundthat includes a photosensitive functional group as a side chain isdeformed (for convenience, referred to as “post-alignment processcompound”), the second alignment film includes the same compound(post-alignment process compound) as the compound that configures thefirst alignment film (post-alignment process compound), and theformation and processing of the second alignment film is different fromthe formation and processing of the first alignment film and when apretilt angle of the liquid crystal molecules which is conferred by thefirst alignment film (that is, by the post-alignment process compound)is θ₁ and a pretilt angle of the liquid crystal molecules which isconferred by the second alignment film (that is, by the post-alignmentprocess compound) is θ₂, θ₁>θ₂. Here, “photosensitive functional group”refers to a group that is able to absorb energy rays. Further, energyrays include ultraviolet radiation, X-rays, electron beams, and thelike. The same applies below.

A manufacturing method of the liquid crystal display device (or amanufacturing method of the liquid crystal display element) according tothe first embodiment of the present disclosure includes: performingformation and processing of a first alignment film composed of a polymercompound that includes a cross-linked functional group or a polymerizedfunctional group as a side chain (for convenience, referred to as“post-alignment process compound”) on one of a pair of substrates andperforming formation and processing of a second alignment film composedof the same polymer compound (pre-alignment process compound) as thepolymer compound that configures the first alignment film on the otherof the pair of substrates; arranging the pair of substrates so that thefirst alignment film and the second alignment film are opposing andsealing a liquid crystal layer that includes liquid crystal moleculeswith negative dielectric constant anisotropy between the first alignmentfilm and the second alignment film; and conferring a pretilt on theliquid crystal molecules by cross-linking or polymerizing the polymercompound (pre-alignment process compound) (that is, a pretilt isconferred on the liquid crystal molecules by the post-alignment processcompound), wherein the formation and processing of the second alignmentfilm is different from the formation and processing of the firstalignment film, and when a pretilt angle of the liquid crystal moleculeswhich is conferred by the first alignment film is θ₁ and a pretilt angleof the liquid crystal molecules which is conferred by the secondalignment film is θ₂, θ₁>θ₂.

While not being limited thereto, the manufacturing method of the liquidcrystal display device (or a manufacturing method of the liquid crystaldisplay element) according to the first embodiment of the presentdisclosure may take the form of cross-linking or polymerizing the sidechain of the polymer compound (pre-alignment process compound) byirradiating the polymer compound with energy rays or heating the polymercompound while aligning the liquid crystal molecules by applying apredetermined electric field on the liquid crystal layer.

Further, in such a case, it is preferable that the energy rays beirradiated while an electric field is applied to the liquid crystallayer so that the liquid crystal molecules are aligned tilted withrespect to the surface of at least one of the pair of substrates, andfurthermore, it is more preferable that the pair of substrates beconfigured by a substrate with pixel electrodes and a substrate withopposing electrodes and the energy rays be irradiated from the side ofthe substrate with the pixel electrodes. Generally, a color filter isformed on the side of the substrate with the opposing electrodes, andsince the energy rays are absorbed by the color filter and there is apossibility that the cross-linked functional group or the polymerizedfunctional group of the alignment film material does not react easily,as described above, it is more preferable that the energy rays beirradiated from the side of the substrate with the pixel electrodes onwhich the color filter is not formed. It is preferable that in a casewhen a color filter is formed on the side of the substrate that includesthe pixel electrodes, energy rays be irradiated on the side of thesubstrate that includes the opposing electrodes. Here, in essence, theazimuth angle (angle of deviation) of the liquid crystal molecules whena pretilt is conferred is regulated by the strength and the direction ofthe electric field and the molecular structure of the alignment filmmaterial, and the polar angle (zenith angle) is regulated by thestrength of the electric field and the molecular structure of thealignment film material. The same is also true of manufacturing methodsof the liquid crystal display devices according to the second and thirdembodiment of the present disclosure described later.

A manufacturing method of the liquid crystal display device (or amanufacturing method of the liquid crystal display element) according tothe second embodiment of the present disclosure includes: performingformation and processing of a first alignment film composed of a polymercompound that includes a photosensitive functional group as a side chain(for convenience, referred to as “post-alignment process compound”) onone of a pair of substrates and performing formation and processing of asecond alignment film composed of the same polymer compound(pre-alignment process compound) as the polymer compound that configuresthe first alignment film on the other of the pair of substrates;arranging the pair of substrates so that the first alignment film andthe second alignment film are opposing and sealing a liquid crystallayer that includes liquid crystal molecules with negative dielectricconstant anisotropy between the first alignment film and the secondalignment film; and conferring a pretilt on the liquid crystal moleculesby deforming the polymer compound (pre-alignment process compound) (thatis, a pretilt is conferred on the liquid crystal molecules by thepost-alignment process compound), wherein the formation and processingof the second alignment film is different from the formation andprocessing of the first alignment film, and when a pretilt angle of theliquid crystal molecules which is conferred by the first alignment filmis θ₁ and a pretilt angle of the liquid crystal molecules which isconferred by the second alignment film is θ₂, θ₁>θ₂.

While not being limited thereto, the manufacturing method of the liquidcrystal display device (or a manufacturing method of the liquid crystaldisplay element) according to the second embodiment of the presentdisclosure may take the form of deforming the side chain of the polymercompound (pre-alignment process compound) by irradiating the polymercompound with energy rays by applying a predetermined electric field onthe liquid crystal layer while aligning the liquid crystal molecules.

A manufacturing method of the liquid crystal display device (or amanufacturing method of the liquid crystal display element) according tothe third embodiment of the present disclosure includes: performingformation and processing of a first alignment film composed of a polymercompound that includes a cross-linked functional group or aphotosensitive functional group as a side chain (for convenience,referred to as “post-alignment process compound”) on one of a pair ofsubstrates and performing formation and processing of a second alignmentfilm composed of the same polymer compound (pre-alignment processcompound) as the polymer compound that configures the first alignmentfilm on the other of the pair of substrates; arranging the pair ofsubstrates so that the first alignment film and the second alignmentfilm are opposing and sealing a liquid crystal layer that includesliquid crystal molecules with negative dielectric constant anisotropybetween the first alignment film and the second alignment film; andconferring a pretilt on the liquid crystal molecules by irradiating thepolymer compound (pre-alignment process compound) with energy rays (thatis, a pretilt is conferred on the liquid crystal molecules by thepost-alignment process compound), wherein the formation and processingof the second alignment film is different from the formation andprocessing of the first alignment film, and when a pretilt angle of theliquid crystal molecules which is conferred by the first alignment filmis θ₁ and a pretilt angle of the liquid crystal molecules which isconferred by the second alignment film is θ₂, θ₁>θ₂.

While not being limited thereto, the manufacturing method of the liquidcrystal display device according to the third embodiment of the presentdisclosure may take the form of irradiating the polymer compound withultraviolet radiation as energy rays while aligning the liquid crystalmolecules by applying a predetermined electric field to the liquidcrystal layer.

According to the liquid crystal display device according to the firstembodiment of the present disclosure, the manufacturing method of theliquid crystal display device according to the first embodiment of thepresent disclosure, the liquid crystal display device according to thesecond embodiment of the present disclosure, the manufacturing method ofthe liquid crystal display device according to the second embodiment ofthe present disclosure, or the manufacturing method of the liquidcrystal display device according to the third embodiment of the presentdisclosure including the favorable forms described above, the formationand processing of the first alignment film includes a rubbing process,the formation and processing of the second alignment film includes arubbing process, and the rubbing process conditions for the secondalignment films are different from the rubbing process conditions forthe first alignment film. That is, the formation and processing of thefirst alignment film is composed of the film formation of the firstalignment film, predrying and calcination, and a rubbing process, theformation and processing of the second alignment film is composed of thefilm formation of the second alignment film, predrying and calcination,and a rubbing process, and the rubbing process conditions for the secondalignment film are able to take a different form from the rubbingprocess conditions for the first alignment film (including a form inwhich a rubbing process is carried out on one of the alignment films anda rubbing process is not carried out on the other alignment film).Alternatively, a form may be taken in which the formation and processingof the first alignment film is composed of film formation, predrying,and calcination of the first alignment film, the formation andprocessing of the second alignment film is composed of film formation,predrying, and calcination of the second alignment film, and the filmformation conditions, predrying conditions, calcination conditions, orthe predrying and calcination conditions of the second alignment filmare different from the film formation conditions, predrying conditions,calcination conditions, or predrying and calcination conditions for thefirst alignment film.

According to the liquid crystal display device according to the firstembodiment of the present disclosure, the manufacturing method of theliquid crystal display device according to the first embodiment of thepresent disclosure, the liquid crystal display device according to thesecond embodiment of the present disclosure, the manufacturing method ofthe liquid crystal display device according to the second embodiment ofthe present disclosure, or the manufacturing method of the liquidcrystal display device according to the third embodiment of the presentdisclosure including the favorable forms described above, it isdesirable that the pretilt angle (first pretilt angle: unit in degrees)θ₁ between the normal vector of the substrate on which the firstalignment film is formed (first substrate) and the liquid crystalmolecules and the pretilt angle (second pretilt angle: unit in degrees)θ₂ between the normal vector of the substrate on which the secondalignment film is formed (second substrate) and the liquid crystalmolecules preferably satisfy θ₁−θ₂≧0.5 and more preferably satisfyθ₁−θ₂≧1.5, and it is desirable that 0≦θ₂≦2.0 and more preferably0.5≦θ₂≦1.0 be satisfied. Alternatively, it is desirable that varioustests be carried out to determine and set the formation and processingof the first alignment film and the formation and processing of thesecond alignment film so that θ₁−θ₂≦0.5 and more preferably θ₁−θ₂≦1.5 issatisfied and 0≦θ₂≦2.0 and more preferably 0.5≦θ₂≦1.0 is satisfied.

Hereinafter, the liquid crystal display device according to the firstembodiment of the present disclosure or the manufacturing method of theliquid crystal display device according to the first embodiment of thepresent disclosure including the preferable forms and configurationsdescribed above may be collectively referred to as simply “the firstembodiment of the present disclosure”, the liquid crystal display deviceaccording to the second embodiment of the present disclosure or themanufacturing method of the liquid crystal display device according tothe second embodiment of the present disclosure including the preferableforms and configurations described above may be collectively referred toas simply “the second embodiment of the present disclosure”, and themanufacturing method of the liquid crystal display device according tothe third embodiment of the present disclosure including the preferableforms and configurations described above may be collectively referred toas simply “the embodiment of the present disclosure”. Further, theliquid crystal display devices according to the first and secondembodiments of the present disclosure may be collectively referred to assimply “the liquid crystal display device of the embodiments of thepresent disclosure”, the manufacturing methods of the liquid crystaldisplay devices according to the first to third embodiments of thepresent disclosure including the preferable forms described above may becollectively referred to as simply “the manufacturing method of theliquid crystal display device of the present disclosure”, and the liquidcrystal display devices of the present disclosure and the manufacturingmethods of the liquid crystal display devices of the present disclosuremay be collectively referred to as simply “the present disclosure”.

According to the first embodiment, the second embodiment, and the thirdembodiment of the present disclosure, the polymer compound(pre-alignment process compound) or the compound that configures thefirst or second alignment film (post-alignment process compound) isfurther able to be composed of a compound including the grouprepresented by Formula 1 as a side chain. Here, for convenience, such aconfiguration will be referred to as “the 1A configuration of thepresent disclosure, the 2A configuration of the present disclosure, andthe 3A configuration of the present disclosure”.—R1-R2-R3  (1)

Here, R1 is a straight-chained or branched divalent organic group of oneor more carbon atoms which may include an ether group or an ester groupand which is bonded to the main chain of the polymerized compound or thecross-linked compound (pre-alignment process compound or post-alignmentprocess compound), or alternatively, R1 is a bonded group of at leastone type selected from a group composed of an ether, an ester, an etherester, an acetal, a ketal, a hemiacetal, and a hemiketal which is bondedto the main chain of the polymerized compound or the cross-linkedcompound (pre-alignment process compound or post-alignment processcompound), R2 is a divalent organic group including a plurality of ringstructures in which one of the atoms that configure the ring structuresis bonded to R1, and R3 is a monovalent group including a hydrogen atom,a halogen atom, an alkyl group, an alkoxy group, and a carbonate group,or a derivative thereof.

Alternatively, according to the first embodiment, the second embodiment,or the third embodiment of the present disclosure, the polymer compound(pre-alignment process compound) or the compound that configures thefirst alignment film and the second alignment film (post-alignmentprocess compound) is able to be configured by a compound that includesthe group represented by Formula 2 as the side chain. Here, forconvenience, such a configuration is referred to as “the 1Bconfiguration of the present disclosure, the 2B configuration of thepresent disclosure, and the 3B configuration of the present disclosure”.Here, the polymer compound (pre-alignment process compound) or thecompound that configures the first alignment film (post-alignmentprocess compound) may be configured not only by the group represented byFormula 2 but also by a compound that includes the group represented byFormula 1 or the group represented by Formula 2 as the side chain.—R11-R12-R13-R14  (2)

Here, R11 is a straight-chained or branched divalent organic group ofone to twenty carbon atoms, preferably three to twelve carbon atomswhich may include an ether group or an ester group and which is bondedto the main chain of the polymerized compound or the cross-linkedcompound (pre-alignment process compound or post-alignment processcompound), or alternatively, R11 is a bonded group of at least one typeselected from a group composed of an ether, an ester, an ether ester, anacetal, a ketal, a hemiacetal, and a hemiketal which is bonded to themain chain of the polymerized compound or the cross-linked compound(pre-alignment process compound or post-alignment process compound), R12is a divalent group including, for example, one of chalcone, cinnamate,cinnamoyl, coumarin, maleimide, benzophenone, norbornene, oryzanol,chitosan, acryloyl, methacryloyl, vinyl, epoxy, and oxetane or anethylene group, R13 is a divalent organic group including a plurality ofring structures, and R14 is a monovalent group including a hydrogenatom, a halogen atom, an alkyl group, an alkoxy group, and a carbonategroup, or a derivative thereof. In some cases, Formula 2 may be modifiedby Formula 2′ below. That is, Formula 2 includes Formula 2′.—R11-R12-R14  (2′)

Alternatively, according to the first embodiment of the presentdisclosure, the compound (post-alignment process compound) obtained bycross-linking the polymer compound (pre-alignment process compound) isconfigured by a side chain and a main chain that supports the side chainwith respect to the first substrate or the second substrate, the sidechain is bonded to the main chain and is configured by a cross-linkedportion in which a portion of the side chain is cross-linked and aterminal structure portion that is bonded to the cross-linked portion,and the liquid crystal molecules are able to be configured to have apretilt conferred thereon by being along the terminal structure portionor by being interposed by the terminal structure portion. Alternatively,according to the second embodiment of the present disclosure, thecompound (post-alignment process compound) obtained by deforming thepolymer compound (pre-alignment process compound) is configured by aside chain and a main chain that supports the side chain with respect tothe first substrate or the second substrate, the side chain is bonded tothe main chain and is configured by a deformed portion in which aportion of the side chain is deformed and a terminal structure portionthat is bonded to the deformed portion, and the liquid crystal moleculesare able to be configured to have a pretilt conferred thereon by beingalong the terminal structure portion or by being interposed by theterminal structure portion. Alternatively, according to the thirdembodiment of the present disclosure, the compound obtained byirradiating the polymer compound with energy rays is configured by aside chain and a main chain that supports the side chain with respect tothe first substrate or the second substrate, the side chain is bonded tothe main chain and is configured by a cross-linked or deformed portionin which a portion of the side chain is cross-linked or deformed and aterminal structure portion that is bonded to the cross-linked ordeformed portion, and the liquid crystal molecules are able to beconfigured to have a pretilt conferred thereon by being along theterminal structure portion or by being interposed by the terminalstructure portion. Here, for convenience, such a configuration will bereferred to as “the 1C configuration of the present disclosure, the 2Cconfiguration of the present disclosure, and the 3C configuration of thepresent disclosure”. According to the 1C configuration of the presentdisclosure, the 2C configuration of the present disclosure, and the 3Cconfiguration of the present disclosure, the terminal structure portionmay have the form of including a mesogenic group. Here, in Formula 1described above, “R2+R3” equates to the terminal structure portion, andin Formula 2 described above, “R13+R14” equates to the terminalstructure portion.

Alternatively, according to the first embodiment of the presentdisclosure, the compound (post-alignment process compound) obtained bycross-linking the polymer compound (pre-alignment process compound) isconfigured by a side chain and a main chain that supports the side chainwith respect to the first substrate or the second substrate, and theside chain is bonded to the main chain and is configured by across-linked portion in which a portion of the side chain iscross-linked and a terminal structure portion that is bonded to thecross-linked portion and that includes a mesogenic group. Here, forconvenience, such a configuration will be referred to as “the 1Dconfiguration of the present disclosure”. Furthermore, the 1Dconfiguration of the present disclosure has a form in which the mainchain and the cross-linked portion are bonded by covalent bonding andthe cross-linked portion and the terminal structure portion are bondedby covalent bonding. Alternatively, according to the second embodimentof the present disclosure, the compound (post-alignment processcompound) obtained by deforming the polymer compound (pre-alignmentprocess compound) is configured by a side chain and a main chain thatsupports the side chain with respect to the first substrate or thesecond substrate, the side chain is bonded to the main chain and isconfigured by a deformed portion in which a portion of the side chain isdeformed and a terminal structure portion that is bonded to the deformedportion and that includes a mesogenic group. Here, for convenience, sucha configuration will be referred to as “the 2D configuration of thepresent disclosure”. Alternatively, according to the third embodiment ofthe present disclosure, the compound (post-alignment process compound)obtained by irradiating the polymer compound (pre-alignment processcompound) with energy rays is configured by a side chain and a mainchain that supports the side chain with respect to the first substrateor the second substrate, the side chain is bonded to the main chain andis configured by a cross-linked or deformed portion in which a portionof the side chain is cross-linked or deformed and a terminal structureportion that is bonded to the cross-linked or deformed portion and thatincludes a mesogenic group. Here, for convenience, such a configurationwill be referred to as “the 3D configuration of the present disclosure”.

According to the first embodiment of the present disclosure thatincludes the 1A to 1D configurations of the present disclosure, the sidechain (more specifically, the cross-linked portion) takes the form ofincluding a photodimerized photosensitive group.

Furthermore, according to the embodiments of the present disclosurewhich include the favorable configurations and forms described above, aconfiguration is possible in which the surface roughness Ra of the firstalignment film of equal to or less than 1 nm is possible. Here, thesurface roughness Ra is regulated by JIS B 0601:2001.

Furthermore, according to the embodiments of the present disclosurewhich include the favorable configurations and forms described above, aconfiguration is possible in which the liquid crystal display devicefurther includes: first electrodes that are formed on the opposing faceof the first substrate that opposes the second substrate; and a firstalignment regulating portion that is provided on the first electrodes,wherein the first alignment film covers the first electrodes, the firstalignment regulating portion, and the opposing face of the firstsubstrate, the first alignment regulating portion is composed of firstslit portions that are formed on the first electrodes, the width of thefirst slit portions is equal to or greater than 2 μm and less than 10μm, and the pitch of the first slit portions is 10 μm to 180 μm,preferably 30 μm to 180 μm, and more preferably 60 μm to 180 μm.

Furthermore, according to the embodiments of the present disclosurewhich include the favorable configurations and forms described above, aconfiguration is possible in which the liquid crystal display devicefurther includes: second electrodes that are formed on the opposing faceof the second substrate that opposes the first substrate; and a secondalignment regulating portion that is provided on the second electrodes,wherein the second alignment film covers the second electrodes, thesecond alignment regulating portion, and the opposing face of the secondsubstrate, the second alignment regulating portion is composed of asecond slit portions that are formed on the second electrodes, the widthof the second slit portions is equal to or greater than 2 μm and lessthan 10 μm, and the pitch of the second slit portions is 10 μm to 180μm, preferably 30 μm to 180 μm, and more preferably 60 μm to 180 μm.

Alternatively, according to the embodiments of the present disclosurewhich include the favorable configurations and forms described above, aconfiguration is possible in which the liquid crystal display devicefurther includes: the first electrodes that are formed on the opposingface of the first substrate that opposes the second substrate; and thesecond alignment regulating portion that is provided on the secondelectrodes, wherein the first alignment film covers the firstelectrodes, the first alignment regulating portion, and the opposingface of the first substrate, and the first alignment regulating portionis composed of protrusions that are provided on the substrates.

Alternatively, according to the embodiments of the present disclosurewhich include the favorable configurations and forms described above, aconfiguration is possible in which the liquid crystal display devicefurther includes: the second electrodes that are formed on the opposingface of the second substrate that opposes the first substrate; and thesecond alignment regulating portion that is provided on the secondelectrodes, wherein the second alignment film covers the secondelectrodes, the second alignment regulating portion, and the opposingface of the second substrate, and the second alignment regulatingportion is composed of protrusions that are provided on the substrates.

According to the embodiments of the present disclosure which include thefavorable configurations and forms described above, a configuration ispossible in which the main chain includes imide bonds within recurringunits is possible. Further, the polymer compound (post-alignment processcompound) may take the form of a structure in which the liquid crystalmolecules are arranged in a predetermined direction with respect to thepair of substrates, that is, not only with respect to the firstsubstrate but also with respect to the second substrate. Furthermore,the pair of substrates may take the form of being configured by asubstrate with pixel electrodes and a substrate with opposingelectrodes, that is, a form in which the first substrate is thesubstrate with the pixel electrodes and the second substrate is thesubstrate with the opposing electrodes, or alternatively, a form inwhich the second substrate is the substrate with the pixel electrodesand the first substrate is the substrate with the opposing electrodes.

According to the liquid crystal display device according to the firstembodiment of the present disclosure, the first alignment film and thesecond alignment film include a compound in which a polymer compoundthat includes a cross-linked functional group or a polymerizedfunctional group is cross-linked or polymerized as the side chain, and apretilt is conferred on the liquid crystal molecules by the cross-linkedor polymerized compound. Therefore, if an electric field is appliedbetween the pixel electrodes and the opposing electrodes, the long axisdirection of the liquid crystal molecules responds in a predetermineddirection with respect to the substrate faces, securing favorabledisplay characteristics. Moreover, since a pretilt is conferred on theliquid crystal molecules by the cross-linked or polymerized compound,the response speed (startup speed of the image display) to the electricfield between the electrodes becomes quicker compared to a case when apretilt is not conferred on the liquid crystal molecules, makingfavorable display characteristics easier to maintain compared to a casewhen a pretilt is conferred without using the cross-linked orpolymerized compound.

According to the manufacturing method of the liquid crystal displaydevice according to the first embodiment of the present disclosure, theliquid crystal layer is sealed between the first alignment film and thesecond alignment film after forming the first alignment film and thesecond alignment film that include a polymer compound that includes across-linked functional group or a polymerized functional group as theside chain. Here, as a whole, the liquid crystal molecules within theliquid crystal layer are in a state of being arranged in a predetermineddirection (for example, horizontal direction, vertical direction, ordiagonal direction) with respect to the first alignment film and secondalignment film surfaces by the first alignment film and the secondalignment film. Next, the polymer compound is cross-linked orpolymerized by reacting a cross-linked functional group or a polymerizedfunctional group while applying an electric field as necessary. Apretilt is thereby able to be conferred on the liquid crystal moleculesin the vicinity of the cross-linked or polymerized compound.Accordingly, compared to a case when a pretilt is not conferred on theliquid crystal molecules, the response speed (startup speed of the imagedisplay) is improved.

According to the liquid crystal display device according to the secondembodiment of the present disclosure, the first alignment film and thesecond alignment film include a compound in which a polymer compoundthat includes a photosensitive functional group is deformed as the sidechain, and a pretilt is conferred on the liquid crystal molecules by thedeformed compound. Therefore, if an electric field is applied betweenthe pixel electrodes and the opposing electrodes, the long axisdirection of the liquid crystal molecules responds in a predetermineddirection with respect to the substrate faces to secure favorabledisplay characteristics, and the response speed (startup speed of theimage display) to the electric field between the electrodes becomesquicker compared to a case when a pretilt is not conferred on the liquidcrystal molecules, making favorable display characteristics easier tomaintain compared to a case when a pretilt is conferred without usingthe deformed compound.

According to the manufacturing method of the liquid crystal displaydevice according to the second embodiment of the present disclosure, theliquid crystal layer is sealed between the first alignment film and thesecond alignment film after forming the first alignment film and thesecond alignment film that include a polymer compound that includes aphotosensitive functional group as the side chain. Here, as a whole, theliquid crystal molecules within the liquid crystal layer are in a stateof being arranged in a predetermined direction (for example, horizontaldirection, vertical direction, or diagonal direction) with respect tothe first alignment film and second alignment film surfaces by the firstalignment film and the second alignment film. Next, the polymer compoundis deformed while applying an electric field as necessary. A pretilt isthereby able to be conferred on the liquid crystal molecules in thevicinity of the deformed compound. Accordingly, compared to a case whena pretilt is not conferred on the liquid crystal molecules, the responsespeed (startup speed of the image display) is improved.

According to the manufacturing method of the liquid crystal displaydevice according to the third embodiment of the present disclosure, apretilt is conferred on the liquid crystal molecules by irradiating thepolymer compound (pre-alignment process compound) with energy rays. Thatis, by cross-linking, polymerizing, or deforming the side chain of thepolymer compound in a state in which the liquid crystal molecules arearranged, the response speed (startup speed of the image display) isimproved compared to a case when a pretilt is not conferred on theliquid crystal molecules.

In addition, according to the embodiments of the present disclosure, theformation and processing of the second alignment film is different fromthe formation and processing of the first alignment film. Therefore, thestate of the pretilt that the second alignment film confers on theliquid crystal molecules positioned in the vicinity thereof is differentfrom the state of the pretilt that the first alignment film confers onthe liquid crystal molecules positioned in the vicinity thereof, andθ₁>θ₂. Therefore, when the application of a voltage is interrupted, theliquid crystal molecules positioned in the vicinity of the secondalignment film are able to be vertically aligned with respect to thesubstrates even more quickly. As a result, it is possible to improve thetermination speed of the image display. Further, since the liquidcrystal molecules are vertically aligned by the second alignment film oraligned by a small pretilt angle, the amount of light transmissionduring black display is able to be reduced, and the contrast is able tobe improved. Furthermore, since the material that configures the firstalignment film and the material that configures the second alignmentfilm are the same in the embodiments of the present disclosure, it ispossible to make changes to the first alignment film over time andchanges to the second alignment film over time (for example, changes tothe leakage current due to physical changes to the alignment films)even, it is possible to improve the long-term reliability of the liquidcrystal display device, and it is possible to simplify the manufacturingprocess of the liquid crystal display device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partial cross-sectional diagram of a liquidcrystal display device of Embodiment 1 of the present disclosure;

FIG. 2 is a schematic partial cross-sectional diagram of a modificationof the liquid crystal display device of Embodiment 1 of the presentdisclosure;

FIG. 3 is a schematic diagram for describing the pretilt of liquidcrystal molecules;

FIG. 4 is a schematic diagram that represents the state of a polymercompound (pre-alignment process compound) within the alignment films fordescribing the manufacturing method of the liquid crystal display deviceillustrated in FIG. 1;

FIG. 5 is a schematic diagram that represents the state of a polymercompound (post-alignment process compound) within the alignment films;

FIG. 6 is a circuit configuration diagram of the liquid crystal displaydevice illustrated in FIG. 1;

FIG. 7 is a cross-sectional schematic diagram for describing orderparameters;

FIG. 8 is a schematic partial cross-sectional diagram of a liquidcrystal display device of Embodiment 2 of the present disclosure;

FIG. 9 is a schematic partial cross-sectional diagram of a modificationof the liquid crystal display device of Embodiment 2 of the presentdisclosure;

FIGS. 10A and 10B are schematic diagrams of first electrodes and firstslit portions when a pixel is viewed from above in the liquid crystaldisplay device of Embodiment 2 of the present disclosure;

FIG. 11 is a flowchart for describing a manufacturing method of theliquid crystal display device of Embodiment 2 of the present disclosure;

FIG. 12 is a schematic cross-sectional diagram of substrates and thelike for describing the manufacturing method of the liquid crystaldisplay device of Embodiment 2 of the present disclosure;

FIG. 13 is a schematic partial cross-sectional diagram of the substratesand the like for describing processes that follow FIG. 12;

FIG. 14 is a schematic partial cross-sectional diagram of the substratesand the like for describing processes that follow FIG. 13;

FIG. 15 is an outline diagram that describes the relationship between across-linked polymer compound and the liquid crystal molecules;

FIG. 16 is an outline diagram that describes the relationship between adeformed polymer compound and the liquid crystal molecules;

FIG. 17 is a schematic cross-sectional diagram of a modification of theliquid crystal display device of Embodiment 2 of the present disclosureillustrated in FIG. 8;

FIG. 18 is a schematic cross-sectional diagram of a modification of theliquid crystal display device of Embodiment 2 of the present disclosureillustrated in FIG. 9;

FIG. 19A is a schematic diagram of the first electrodes and the firstslit portions and second electrodes and second slit portions when apixel is viewed from above, and FIG. 19B is schematic diagram of thesecond electrodes and the second slit portions when a pixel is viewedfrom above;

FIG. 20A is a schematic diagram of a modification of the firstelectrodes and the first slit portions and the second electrodes and thesecond slit portions when a pixel is viewed from above, and FIG. 20B isa schematic diagram of a modification of the second electrodes and thesecond slit portions when a pixel is viewed from above;

FIG. 21A is a schematic diagram of another modification of the firstelectrodes and the first slit portions and the second electrodes and thesecond slit portions when a pixel is viewed from above, and FIG. 21B isanother schematic diagram of a modification of the second electrodes andthe second slit portions when a pixel is viewed from above; and

FIGS. 22A and 22B are diagrams that schematically illustrate the stateof the twist of the long axis of a liquid crystal molecule group.

DETAILED DESCRIPTION OF EMBODIMENTS

Although the present disclosure will be described below based on theembodiments and examples of the present disclosure with reference to thedrawings, the present disclosure is not limited to the embodiments andexamples of the present disclosure, and the various numerical values andmaterials in the embodiments and examples of the present disclosure areexamples. Here, description will be given in the flowing order.

1. Descriptions Relating to Common Configurations and Structures inLiquid Crystal Display Devices According to Embodiments of PresentDisclosure

2. Descriptions of Liquid Crystal Display Devices and ManufacturingMethods Thereof of Embodiments of Present Disclosure Based onEmbodiments of Present Disclosure

3. Descriptions of Liquid Crystal Display Devices and ManufacturingMethods Thereof of Embodiments of Present Disclosure Based on Examples,and the like

[Descriptions Relating to Common Configurations and Structures in LiquidCrystal Display Devices (Liquid Crystal Display Element) According toEmbodiments of Present Disclosure]

A schematic partial cross-sectional diagram of a liquid crystal displaydevice (or liquid crystal display element) according to an embodiment ofthe present disclosure is illustrated in FIG. 1. The liquid crystaldisplay device includes a plurality of pixels 10 (10A, 10B, 10C . . . ).Furthermore, according to the liquid crystal display device (liquidcrystal display element), a liquid crystal layer 40 that includes liquidcrystal molecules 41 via alignment films 22 and 32 is provided between aTFT (Thin Film Transistor) substrate 20 and a CF (Color Filter)substrate 30. Such a liquid crystal display device (liquid crystaldisplay element) is a so-called transmission type, and the display modethereof is the vertical alignment (VA) mode. In FIG. 1, a non-drivenstate in which a driving voltage is not applied is represented. Here, inreality, the pixels 10 are configured, for example, by subpixels thatdisplay red images, subpixels that display green images, subpixels thatdisplay blue images, and the like.

Here, the TFT substrate 20 equates to the first substrate, and the CFsubstrate 30 equates to the second substrate. Further, pixel electrodes20B and an alignment film 22 that are provided on the first substrate(TFT substrate) 20 equate to the first electrodes and the firstalignment film, and opposing electrodes 30B and an alignment film 32that are provided on the second substrate (CF substrate) 30 equate tothe second electrodes and the second alignment film.

That is, the liquid crystal display device includes liquid crystaldisplay element with the first alignment film 22 and the secondalignment film 32 that are provided on opposing face sides of the pairof substrates 20 and 30, and the liquid crystal layer 40 that isprovided between the first alignment film 22 and the second alignmentfilm 32 and that includes the liquid crystal molecules 41 with negativedielectric constant anisotropy.

Furthermore, the first alignment film 22 includes a compound in whichthe polymer compound that includes a cross-linked functional group or apolymerized functional group as a side chain (post-alignment processcompound), the second alignment film 32 includes the same compound(post-alignment process compound) as the compound that configures thefirst alignment film 22 (post-alignment process compound), the formationand processing of the second alignment film 32 is different from theformation and processing of the first alignment film 22, and when thepretilt angle (first pretilt angle) of the liquid crystal molecules 41which is conferred by the first alignment film (that is, by thepost-alignment process compound) is θ₁ and the pretilt angle (secondpretilt angle) of the liquid crystal molecules 41 which is conferred bythe second alignment film 32 (that is, by the post-alignment processcompound) is θ₂, θ₁>θ₂. Here, in the description below, the expression“second pretilt angle θ₂” includes 0 degrees.

More specifically, the liquid crystal display device is composed of anarrangement of a plurality of pixels 10 that include the first substrate(TFT substrate) 20 and the second substrate (CF substrate) 30, the firstelectrodes (pixel electrodes) 20B that are formed on the opposing faceof the first substrate 20 that opposes the second substrate 30, thefirst alignment film 22 that covers the first electrodes (pixelelectrodes) 20B and the opposing face of the first substrate (TFTsubstrate) 20, the second electrodes (opposing electrodes) 30B that areformed on the opposing face of the second substrate (CF substrate) 30that opposes the first substrate (TFT substrate) 20, the secondalignment film 32 that covers the second electrodes (opposingelectrodes) 30B and the opposing face of the second substrate (CFsubstrate) 30, and the liquid crystal layer 40 that is provided betweenthe first alignment film 22 and the second alignment film 32 and thatincludes the liquid crystal molecules 41.

The TFT substrate 20 composed of a glass substrate has a plurality ofpixel electrodes 20B that are arranged on the surface of the side thatopposes the CF substrate 30 composed of a glass substrate in a matrixshape, for example. Furthermore, TFT switching elements that includegate source drains and the like that respectively drive the plurality ofpixel electrodes 20B, gate lines and source lines that are connected tosuch TFT switching elements, and the like (not shown) are provided. Apixel electrode 20B is provided for every pixel that is electricallyseparated by a pixel separation portion, and is configured by a materialwith transparency such as, for example, ITO (indium tin oxide).

On the CF substrate 30, color filters (not shown) that are configured,for example, by red (R), green (G), and blue (B) striped filters and theopposing electrodes 30B are arranged on approximately the entirety ofthe effective display region on the opposing face with the TFT substrate20. Similarly to the pixel electrodes 20B, the opposing electrodes 30Bare configured by a material with transparency such as, for example,ITO. The opposing electrodes 30B are so-called solid electrodes thathave not been patterned.

The first alignment film 22 is provided on the surface of the liquidcrystal layer 40 side of the TFT substrate 20 to cover the pixelelectrodes 20B. The second alignment film 32 is provided on the surfaceof the liquid crystal layer 40 side of the CF substrate 30 to cover theopposing electrodes 30B. The first alignment film 22 and the secondalignment film 32 regulate the alignment of the liquid crystal molecules41, and here, have a function of conferring a pretilt on the liquidcrystal molecules 41 (41A, 41B) in the vicinity of the substrates whilealigning the liquid crystal molecules 41 that are positioned away fromthe substrates in the vertical direction with respect to the substratefaces.

FIG. 6 represents a circuit configuration of the liquid crystal displaydevice illustrated in FIG. 1.

As illustrated in FIG. 6, the liquid crystal display device isconfigured to include the liquid crystal display element including aplurality of pixels 10 provided within a display region 60. With such aliquid crystal display device, a source driver 61 and a gate driver 62,a timing controller 63 that controls the source driver 61 and the gatedriver 62, and a power source circuit 64 that supplies power to thesource driver 61 and the gate driver 62 are provided in the surroundingsof the display region 60.

The display region 60 is a region in which an image is displayed, and isa region that is configured to be able to display an image by aplurality of pixels 10 being arranged in a matrix shape. Here, in FIG.6, other than the display region 60 including the plurality of pixels 10being illustrated, a region corresponding to four pixels 10 isillustrated separately enlarged.

In the display region 60, in addition to a plurality of source lines 71being arranged in the line direction, a plurality of gate lines 72 arearranged in the column direction, and the pixels 10 are respectivelyarranged at positions in which the source lines 71 and the gate lines 72intersect one another. Each pixel 10 is configured to include atransistor 121 and a capacitor 122 along with the pixels electrodes 20Band the liquid crystal layer 40. In each transistor 121, a sourceelectrode is connected to a source line 71, a gate electrode isconnected to a gate line 72, and a drain electrode is connected to acapacitor 122 and a pixel electrode 20B. Each source line 71 isconnected to a source driver 61, and image signals are supplied from thesource driver 61. Each gate line 72 is connected to a gate driver 62,and scan signals are sequentially supplied from the gate driver 62.

The source driver 61 and the gate driver 62 select a specific pixel 10from the plurality of pixels 10.

The timing controller 63 outputs image signals (for example, each of theimage signals RGB that correspond to red, green, and blue) and sourcedriver control signals for controlling the actions of the source driver61, for example, to the source driver 61. Further, the timing controller63 outputs gate driver control signals for controlling the actions ofthe gate driver 62, for example, to the gate driver 62. Source driversignals include, for example, horizontally synchronized signals, startpulse signals, source driver clock signals, and the like. Gate drivercontrol signals include, for example, vertically synchronized signals,gate driver clock signals, and the like.

With such a liquid crystal display device, an image is displayed byapplying a driving voltage between the first electrodes (pixelelectrodes) 20B and the second electrodes (opposing electrodes) 30B inthe manner below. Specifically, the source driver 61 supplies individualimage signals to a predetermined source line 71 based on an image signalthat is similarly input from the timing controller 63 by an input of asource driver control signal from the timing controller 63. In addition,the gate driver 62 sequentially supplies scan signals to the gate lines72 at predetermined timings by the input of a gate driver control signalfrom the timing controller 63. In so doing, the pixel 10 positioned atthe intersecting portion between the source line 71 to which the imagesignal is supplied and the gate line 72 to which the scan signal issupplied is selected, and a driving voltage is supplied to the pixel 10.

The present disclosure will be described below based on the embodimentsof the present disclosure (abbreviated to “embodiments”) and examples.

Embodiment 1

Embodiment 1 relates to the VA mode liquid crystal display device (orliquid crystal display element) according to the first embodiment of thepresent disclosure and to the manufacturing methods of the liquidcrystal display device (or liquid crystal display element) according tothe first embodiment or the third embodiment of the present disclosure.In Embodiment 1, the first alignment film 22 includes a compound(post-alignment process compound) in which the polymer compound(pre-alignment process compound) that includes a cross-linked functionalgroup or a polymerized functional group as a side chain is cross-linkedor polymerized, and the second alignment film 32 includes the samecompound as the compound that configures the first alignment film. Thatis, the first alignment film 22 and the second alignment film 32 arecomposed of the same polymer compound. Furthermore, a pretilt isconferred on the liquid crystal molecules by a cross-liked orpolymerized compound. Here, the post-alignment process compound isgenerated by cross-linking or polymerizing the polymer compound orirradiating the polymer compound with energy rays after forming thealignment films 22 and 32 in a state of including one or two or moretypes of a polymer compound (pre-alignment process compound) thatincludes a main chain and a side chain and providing the liquid crystallayer 40. Furthermore, the post-alignment process compound has astructure in which the liquid crystal molecules are arranged in apredetermined direction (specifically, a diagonal direction and forexample, the vertical direction) with respect to a pair of substrates(specifically, the TFT substrate 20 and the CF substrate 30). In such amanner, since it is possible to confer a pretilt and, for example, avertical alignment to the liquid crystal molecules 41 in the vicinity ofthe alignment films 22 and 32 by the post-alignment process compoundbeing included in the alignment films 22 and 32 by cross-linking orpolymerizing the polymer compound or irradiating the polymer compoundwith energy rays, the response speed (startup speed of the image displayand termination speed of image display) is quickened, and the displaycharacteristics are improved.

Here, the formation and processing of the second alignment film 32 isdifferent from the formation and processing of the first alignment film22, and as a result, the relationship θ₁>θ₂ is conferred between thefirst pretilt angle θ₁ of the liquid crystal molecules conferred by thefirst alignment film and the second pretilt angle θ₂ of the liquidcrystal molecules conferred by the second alignment film 32.Accordingly, when the application of a voltage is interrupted, theliquid crystal molecules that are positioned in the vicinity of thesecond alignment film 32 are able to be aligned in the verticaldirection with respect to the substrates even quicker. It is thereforepossible to improve the termination speed of the image display. Further,since the liquid crystal molecules are vertically aligned by the secondalignment film 32 or aligned with a small tilt angle, it is possible toreduce the amount of light transmission during black display, and it ispossible to improve the contrast further. Moreover, since the materialthat configures the first alignment film 22 and the material thatconfigures the second alignment film 32 are the same, it is possiblemake changes to the first alignment film 22 over time and changes to thesecond alignment film 32 over time even, it is possible to improve thelong-term reliability of the liquid crystal display device and it ispossible to simplify the manufacturing process of the liquid crystaldisplay device.

It is preferable that the pre-alignment process compound include astructure with high heat resistance as the main chain. In so doing, evenif the liquid crystal display device (liquid crystal display element) isexposed to a high heat environment, since the post-alignment processcompound within the alignment films 22 and 32 maintains alignmentregulating capabilities with respect to the liquid crystal molecules 41,display characteristics such as the contrast are favorably maintainedalong with the response characteristics, and reliability is secured.Here, it is preferable that the main chain include imide bonds withinrecurring units. The polymer compound including the polyimide structurerepresented by Formula 3, for example, is exemplified as a pre-alignmentprocess compound that includes imide bonds in the main chain. Thepolymer compound including the polyimide structure illustrated inFormula 3 may be configured by one of the types of the polyimidestructures illustrated in Formula 3, a plurality of types may beincluded by being randomly bonded, or another structure other than thestructure illustrated in Formula 3 may be included.

Here, R1 is a tetravalent organic group, R2 is a divalent organic group,and n1 is an integer of equal to or greater than 1.

Although R1 and R2 in Formula 3 are arbitrary as long as R1 and R2 aretetravalent or divalent groups configured to include carbon atoms, it ispreferable that a cross-linked functional group or a polymerizedfunctional group be included in one of R1 and R2 as the side chain. Thereason is that it is then easy to obtain sufficient alignment regulatingcapabilities with the post-alignment process compound.

Further, with the pre-alignment process compound, it is sufficient ifthe side chains have a plurality of bonds with the main chain, and atleast one of the plurality of side chains includes a cross-linkedfunctional group or a polymerized functional group. That is, thepre-alignment process compound may include side chains that are notcross-linked other than side chains that are cross-linked. The sidechains that include cross-linked functional groups or polymerizedfunctional groups may be one type or a plurality of types. Although across-linked functional group or a polymerized functional group isarbitrary as long as the cross-linked functional group or thepolymerized functional group are functional groups that are able toreact by cross-linking after the liquid crystal layer 40 is formed, andmay be a group that forms a cross-linked structure by an opticalreaction or a group that forms a cross-linked structure by a heatreaction, a photoreactive cross-linked functional group or polymerizedfunctional group (photosensitive group with photosensitivity) that formsa cross-linked structure by an optical reaction is preferable. Thereason is that it is then easy to regulate the alignment of the liquidcrystal molecules 41 in a predetermined direction, enabling themanufacture of a liquid crystal display device (liquid crystal displayelement) with improved response characteristics as well as favorabledisplay characteristics.

Examples of a photoreactive cross-linked functional group(photosensitive group with photosensitivity, for example, photodimerizedphotosensitive group) include the structure of one of chalcone,cinnamate, cinnamoyl, coumarin, maleimide, benzophenone, norbornene,oryzanol, and chitosan. Out of the above, the group represented byFormula 41 is an example of a group that includes the structure ofchalcone, cinnamate, or cinnamoyl. If a pre-alignment process compoundincluding a side chain that includes the group illustrated in Formula 41is cross-linked, the structure illustrated in Formula 42 is formed, forexample. That is, the post-alignment process compound generated from thepolymer compound that includes the group illustrated in Formula 41includes the structure illustrated in Formula 42 with a cyclobutaneskeleton. Here, for example, a photoreactive cross-linked functionalgroup such as maleimide may in some cases exhibit not only aphotodimerization reaction but also a polymerization reaction.Therefore, a polymer compound that includes a cross-linked functionalgroup or a polymerized functional group is expressed as a cross-linkedor polymerized compound.

Here, R3 is a divalent group including an aromatic ring, R4 or R1 is amonovalent group including one or two or more ring structures, and R5 isa hydrogen atom, an alkyl group, or a derivative thereof.

R3 in Formula 41 is arbitrary as long as R3 is a divalent groupincluding an aromatic ring such as a benzene ring, and other than anaromatic ring, a carbonyl group, ether bonds, ester bonds, or ahydrocarbon group may be included. Further, R4 in Formula 41 isarbitrary as long as R4 is a monovalent group including one or two ormore ring structures, and other than the ring structures, a carbonylgroup, ether bonds, an ester group, a hydrocarbon group, a halogen atom,and the like may be included. The ring structure of R4 is arbitrary aslong as the ring structure is a ring that includes carbon as the elementthat configures the skeleton, and for example, an aromatic ring, aheterocyclic ring, an aliphatic ring, a ring structure in which thearomatic ring, the heterocyclic ring, or the aliphatic ring areconsolidated or condensed, and the like are exemplified as such a ringstructure. R5 in Formula 41 is arbitrary as long as R5 is a hydrogenatom, an alkyl group, or a derivative thereof. Here, “derivative” refersto a group in which a portion or all of the hydrogen atoms that thealkyl group has are substituted by a substituent such as halogen atoms.Further, the number of carbon atoms in the alkyl group that isintroduced as R5 is arbitrary. Hydrogen atoms or a methyl group isfavorable as R5. The reason is that favorable cross-link reactivity isthen obtained.

Each R3 in Formula 42 may be the same as or different from one another.The same is also true of each R4 and each R5 in Formula 41. R3, R4, andR5 in Formula 42 include, for example, those that are the same as R3,R4, and R5 in Formula 41.

Examples of the group illustrated in Formula 41 include, for example,the groups represented in Formulae 41-1 to 41-33. However, as long asthe group has the structure illustrated in Formula 41, the group is notlimited to the groups illustrated in Formulae 41-1 to 41-33.

It is preferable that the pre-alignment process compound include astructure for aligning the liquid crystal molecules 41 in the verticaldirection with respect to the substrate faces (hereinafter referred toas “vertical alignment inducing structure portion”). The reason is thateven if the alignment films 22 and 32 do not include a compound thatincludes a vertical alignment inducing structure mechanism portion(so-called normal vertical alignment agent) separately from thepost-alignment process compound, the alignment regulation of theentirety of the liquid crystal molecules 41 becomes possible. Anotherreason is that alignment films 22 and 32 that are able to exhibitalignment regulation functions with respect to the liquid crystal layer40 more evenly are more easily formed than in a case when the compoundthat includes the vertical alignment inducing structure portion isincluded. In the pre-alignment process compound, the vertical alignmentinducing structure portion may be included in the main chain, may beincluded in the side chain, or may be included in both. Further, in acase when the pre-alignment process compound includes the polyimidestructure illustrated in Formula 3, it is preferable that the two typesof structures of a structure that includes a vertical alignment inducingstructure portion as R2 (recurring units) and a structure that includesa cross-linked functional group or a polymerized functional group as R2(recurring units) be included, since the two types of structures areeasily obtainable. Here, if the vertical alignment inducing structureportion is included in the pre-alignment process compound, the verticalalignment inducing structure portion is also included in thepost-alignment process compound.

Examples of the vertical alignment inducing structure portion include analkyl group with ten or more carbon atoms, an alkyl halide group withten or more carbon atoms, an alkoxy group with ten or more carbon atoms,an alkoxy halide group with ten or more carbon atoms, an organic groupincluding a ring structure, or the like. Specifically, the structurerepresented by Formulae 5-1 to 5-6 and the like, for example, areexemplified as structures that include a vertical alignment inducingstructure portion.

Here, Y1 is an alkyl group with ten or more carbon atoms, an alkoxygroup with ten or more carbon atoms, or a monovalent group with a ringstructure. Further, Y2 to 1Y5 are hydrogen atoms, alkyl groups with tenor more carbon atoms, alkoxy groups with ten or more carbon atoms, ormonovalent organic groups including a ring structure, and at least oneof Y2 and Y3, at least one of Y4 to Y6, at least one of Y7 and Y8, atleast one of Y9 to Y12, and at least one of Y13 to Y15 is an alkyl groupwith ten or more carbon atoms, an alkoxy group with ten or more carbonatoms, or a monovalent group including a ring structure. However, Y11and Y12 may form a ring structure by bonding.

Further, the groups represented by Formulae 6-1 to 6-23 and the like areexemplified as monovalent organic groups including a ring structure asthe vertical alignment inducing structure portion. The groupsrepresented by Formulae 7-1 to 7-7 and the like are exemplified asdivalent organic groups including a ring structure as the verticalalignment inducing structure portion.

Here, a1 to a3 are integers equal to or greater than 0 and equal to orless than 21.

Here, a1 is an integer equal to or greater than 0 and equal to or lessthan 21.

Here, the vertical alignment inducing structure portion is not limitedto the group above as long as the vertical alignment inducing structureportion includes a structure that functions so that the liquid crystalmolecules 41 are aligned in the vertical direction with respect to thesubstrate faces.

Further, if expressed according to the configuration of the 1Aconfiguration, the 2A configuration (refer to Embodiment 3 below), orthe 3A configuration of the present disclosure, the polymer compoundbefore cross-linking (pre-alignment process compound) is composed, otherthan by a cross-linked functional group or a polymerized functionalgroup, by a compound that includes the group represented by Formula 1 asthe side chain. Since the group shown in Formula 1 is able to move alongthe liquid crystal molecules 41, when the pre-alignment process compoundis cross-linked, the group shown in Formula 1 is fixed along with thecross-linked functional group or the polymerized functional group in astate of being along the alignment direction of the liquid crystalmolecules 41. Furthermore, since it becomes easier to regulate thealignment direction of the liquid crystal molecules 41 in apredetermined direction by the fixed group shown in Formula 1, itbecomes easier to manufacture a liquid crystal display device withfavorable display characteristics.—R1-R2-R3  (1)

Here, R1 is a straight-chained or branched divalent organic group of oneor more carbon atoms which may include an ether group or an ester groupand which is bonded to the main chain of the polymerized compound or thecross-linked compound (pre-alignment process compound or post-alignmentprocess compound), or alternatively, R1 is a bonded group of at leastone type selected from a group composed of an ether, an ester, an etherester, an acetal, a ketal, a hemiacetal, and a hemiketal which is bondedto the main chain of the polymerized compound or the cross-linkedcompound (pre-alignment process compound or post-alignment processcompound). R2 is a divalent organic group including a plurality of ringstructures in which one of the atoms that configure the ring structuresis bonded to R1. R3 is a monovalent group including a hydrogen atom, ahalogen atom, an alkyl group, an alkoxy group, and a carbonate group, ora derivative thereof.

R1 in Formula 1 is a part for functioning as a spacer portion forconferring, along with fixing R2 and R3 to the main chain, a largepretilt on the liquid crystal molecules if a long R1 is selected and foreasily fixing the pretilt angle if a short R1 is selected, and forexample, an alkylene group or the like is exemplified as R1. Thealkylene group may include ether bonds between the carbon atoms in themiddle, and there may be one or two or more locations in which suchether bonds exist. Further, R1 may include a carbonyl group or acarbonate group. It is preferable that the number of carbon atoms in R1be six or more. The reason is that since the group shown in Formula 1and the liquid crystal molecules 41 mutually act on each other, it isnot easy for the group to be along the liquid crystal molecules 41. Itis preferable that the number of carbon atoms be determined so that thelength of R1 is similar to the length of the terminal chain of theliquid crystal molecules 41.

R2 in Formula 1 is a part that is along a ring structure (core part)included in general nematic liquid crystal molecules. The same group orskeleton as the ring structure included in the liquid crystal moleculessuch as, for example, a 1,4-phenelene group, a 1,4-cyclohexylene group,a pyrimidene-2,5-diyl group, a 1,6-naphthalene group, a divalent groupwith a steroidal skeleton, a derivative thereof, and the like areexemplified as R2. Here, a “derivative” is a group in which one or twoor more substituents are introduced to the series of groups above.

R3 in Formula 1 is a portion along the terminal chain of the liquidcrystal molecules, and for example, an alkyl group, an alkyl hydridegroup, and the like are exemplified as R3. However, with the alkylhydride group, it is sufficient if the hydrogen atoms of at least one ofthe alkyl groups are substituted by halogen atoms, and the type of thehalogen atoms is arbitrary. The alkyl group or the alkyl hydride groupmay include ether bonds between the carbon atoms in the middle, andthere may be one or two or more locations in which such ether bondsexist. Further, R3 may include a carbonyl group or a carbonate group.For the same reasons as with R1, it is preferable that the number ofcarbon atoms in R3 be six or more.

Specifically, the monovalent groups represented by Formulae 1-1 to 1-12and the like, for example, are exemplified as the group shown in Formula1.

Here, the group illustrated in Formula 1 is not limited to the groupsdescribed above as long as the group is able to move along the liquidcrystal molecules 41.

Alternatively, if expressed according to the configuration of the 1Aconfiguration, the 2A configuration (refer to Embodiment 2 below), orthe 3A configuration of the present disclosure, the polymer compoundbefore cross-linking (pre-alignment process compound) is composed of acompound that includes the group represented by Formula 2 as the sidechain. Since the polymer compound includes parts that are along theliquid crystal molecules 41 and parts in which the tilt angle isregulated in addition to parts to be cross-linked, it is possible to fixthe side chain parts that are along the liquid crystal molecules 41 in astate of being along the liquid crystal molecules 41. In so doing, sinceit becomes easier to regulate the alignment of the liquid crystalmolecules 41 in a predetermined direction, it becomes easier tomanufacture a liquid crystal display device with favorable displaycharacteristics.—R11-R12-R13-R14  (2)

Here, R11 is a straight-chained or branched divalent organic group ofone to twenty carbon atoms, preferably three to twelve carbon atomswhich may include an ether group or an ester group and which is bondedto the main chain of the polymerized compound or the cross-linkedcompound (pre-alignment process compound or post-alignment processcompound), or alternatively, R11 is a bonded group of at least one typeselected from a group composed of an ether, an ester, an ether ester, anacetal, a ketal, a hemiacetal, and a hemiketal which is bonded to themain chain of the polymerized compound or the cross-linked compound(pre-alignment process compound or post-alignment process compound). R12is a divalent group including, for example, one of chalcone, cinnamate,cinnamoyl, coumarin, maleimide, benzophenone, norbornene, oryzanol,chitosan, acryloyl, methacryloyl, vinyl, epoxy, and oxetane or anethylene group. R13 is a divalent organic group including a plurality ofring structures. R14 is a monovalent group including a hydrogen atom, ahalogen atom, an alkyl group, an alkoxy group, and a carbonate group, ora derivative thereof.

R11 in Formula 2 is a part that regulates the tilt angle in thepre-alignment process compound, and it is preferable that thepre-alignment process compound be flexible. The group described withregard to R1 in Formula 1 is exemplified, for example, as R11. With thegroup shown in Formula 2, since R12 to R14 tend to move with R11 as theaxis, R13 and R14 are easily able to be along the liquid crystalmolecules 41. It is preferable that the number of carbon atoms in R11 be6 to 10.

R12 in Formula 2 is a part that includes a cross-linked functional groupor a polymerized functional group. As described above, such across-linked functional group or polymerized functional group may be agroup that forms a cross-linked structure by an optical reaction or maybe a group that forms a cross-linked structure by a heat reaction.Specifically, for example, a divalent group including the structure ofat least one of chalcone, cinnamate, cinnamoyl, coumarin, maleimide,benzophenone, norbornene, oryzanol, chitosan, acryloyl, methacryloyl,vinyl, epoxy, and oxetane, an ethynylene group, and the like areexemplified as R12.

R13 in Formula 2 is a part that is able to be along the core part of theliquid crystal molecules 41, and the group described in relation to R2in Formula 1 or the like, for example, is exemplified as R13.

R14 in Formula 2 is a part that is along the terminal chain of theliquid crystal molecules 41, and the group described in relation to R3in Formula 1 or the like, for example, is exemplified as R14.

Specifically, the monovalent group represented by Formulae 2-1 to 2-11or the like, for example, is exemplified as the group shown in Formula2.

Here, n is an integer equal to or greater than 3 and equal to or lessthan 20.

Here, the group shown in Formula 2 is not limited to the groups above aslong as the group includes the four parts (R11 to R14) described above.

Alternatively, if expressed according to the 1C configuration of thepresent disclosure, a compound (post-alignment process compound)obtained by cross-linking the polymer compound (pre-alignment processcompound) is configured by a side chain and a main chain that supportsthe side chain with respect to the substrates, the side chain isconfigured by being bonded to the main chain, a cross-linked portion inwhich a portion of the side chain is cross-linked, and a terminalstructure portion that is bonded to the cross-linked portion, and apretilt is conferred by the liquid crystal molecules being along theterminal structure portion or being interposed by the terminal structureportion. Further, if expressed according to the 2C configuration of thepresent disclosure (refer to Embodiment 3 below), a compound(post-alignment process compound) obtained by deforming the polymercompound (pre-alignment process compound) is configured by a side chainand a main chain that supports the side chain with respect to thesubstrates, the side chain is configured by being bonded to the mainchain, a deformed portion in which a portion of the side chain isdeformed, and a terminal structure portion that is bonded to thedeformed portion, and a pretilt is conferred by the liquid crystalmolecules being along the terminal structure portion or being interposedby the terminal structure portion. Further, if expressed according tothe 3C configuration of the present disclosure, a compound obtained byirradiating the polymer compound with energy rays is configured by aside chain and a main chain that supports the side chain with respect tothe substrates, the side chain is configured by being bonded to the mainchain, a cross-linked or deformed portion in which a portion of the sidechain is cross-linked or deformed, and a terminal structure portion thatis bonded to the cross-linked or deformed portion, and a pretilt isconferred by the liquid crystal molecules being along the terminalstructure portion or being interposed by the terminal structure portion.

Here, according to the 1C configuration of the present disclosure, thecross-linked portion in which a portion of the side chain iscross-linked equates to R12 of Formula 2 (however, after cross-linking).Further, the terminal structure portion equates to R13 and R14 inFormula 2. Here, with the post-alignment process compound, a pretilt isconferred on the liquid crystal molecules, for example, when thecross-linked portions of two side chains extending from the main chainare cross-linked to each other, by a portion of the liquid crystalportions being almost interposed between a terminal structure portionextending from one of the cross-linked portions and a terminal structureportion extending from the other cross-linked portion while the terminalstructure portions are fixed in a state of holding a predetermined anglewith respect to the substrates. Here, while such a state is illustratedin the outline diagram of FIG. 15, the example illustrated in FIG. 15illustrates the state when the manufacturing method of the liquidcrystal display device of Embodiment 2 described later is adopted.

Alternatively, if expressed according to the 1D configuration of thepresent disclosure, a compound (post-alignment process compound)obtained by cross-linking the polymer compound (pre-alignment processcompound) is configured by a side chain and a main chain that supportsthe side chain with respect to the substrates, the side chain isconfigured by being bonded to the main chain, a cross-linked portion inwhich a portion of the side chain is cross-linked, and a terminalstructure portion that is bonded to the cross-linked portion and thatincludes a mesogenic group. Here, the side chain takes the form ofincluding a photodimerized photosensitive group. Further, the main chainand the cross-linked portion are bonded by covalent bonds and thecross-linked portion and the terminal structure portion are bonded bycovalent bonds. Further, if expressed according to the 2D configurationof the present disclosure (refer to Embodiment 3 below), a compound(post-alignment process compound) obtained by deforming the polymercompound (pre-alignment process compound) is configured by a side chainand a main chain that supports the side chain with respect to thesubstrates, the side chain is configured by being bonded to the mainchain, a deformed portion in which a portion of the side chain isdeformed, and a terminal structure portion that is bonded to thedeformed portion and that includes a mesogenic group. Further, ifexpressed according to the 3D configuration of the present disclosure, acompound (post-alignment process compound) obtained by irradiating thepolymer compound (pre-alignment process compound) with energy rays isconfigured by a side chain and a main chain that supports the side chainwith respect to the substrates, the side chain is configured by beingbonded to the main chain, a cross-linked or deformed portion in which aportion of the side chain is cross-linked or deformed, and a terminalstructure portion that is bonded to the cross-linked or deformed portionand that includes a mesogenic group.

Here, according to the 1D configuration of the present disclosure, asdescribed above, a group that includes the structure of one of chalcone,cinnamate, cinnamoyl, coumarin, maleimide, benzophenone, norbornene,oryzanol, and chitosan, for example, is exemplified as thephotodimerized photosensitive group that is a cross-linked functionalgroup or a polymerized functional group (photosensitive functionalgroup. A group that includes the structure of one of acryloyl,methacryloyl, vinyl, epoxy, and oxetane, for example, is exemplified asthe polymerized functional group. A rigid mesogenic group thatconfigures the terminal structure portion may exhibit liquidcrystallinity or as a side chain or may not exhibit liquidcrystallinity, and as a specific structure, a steroid derivative, acholesterol derivative, biphenyl, triphenyl, naphthalene, and the likeare exemplified. Further, R13 and R14 in Formula 2 are exemplified asthe terminal structure portion.

Further, the alignment films 22 and 32 may include other verticalalignment agents other than the post-alignment process compounddescribed above. Polyamide that includes a vertical alignment inducingstructure portion, polysiloxane that includes a vertical alignmentinducing structure portion, and the like are exemplified as othervertical alignment agents.

The liquid crystal layer 40 includes the liquid crystal molecules 41with negative dielectric constant anisotropy. The liquid crystalmolecules 41 have negative dielectric constant anisotropy by beingrotationally symmetrical with the long axis and the short axis thatintersect each other respectively as the center axis.

The liquid crystal molecules 41 are categorized into liquid crystalmolecules 41A that are maintained by the first alignment film 22 in thevicinity of the interface with the first dielectric film 22, liquidcrystal molecules 41B that are maintained by the second alignment film32 in the vicinity of the interface with the second alignment film 32,and liquid crystal molecules 41C that are the remainder. The liquidcrystal molecules 41C are positioned in an intermediate region in thethickness direction of the liquid crystal layer 40, and are arranged sothat the long axis direction (director) of the liquid crystal molecules41C is approximately vertical to the first substrate 20 and the secondsubstrate 30 when the driving voltage is in an OFF state. Further, theliquid crystal molecules 41B are positioned in the vicinity of thesecond alignment film 32 and the long axis direction (director) of theliquid crystal molecules 41B is aligned at the second pretilt angle θ₂with respect to the second substrate 30 when the driving voltage is inan OFF state. Furthermore, the liquid crystal molecules 41A arepositioned in the vicinity of the first alignment film 22 and the longaxis direction (director) of the liquid crystal molecules 41A is alignedat the first pretilt angle θ₁ (>θ₂) with a tilt with respect to thefirst substrate 20 when the driving voltage is in an OFF state.

Here, when the driving voltage is turned ON, the directors of the liquidcrystal molecules 41A are aligned tilted to be parallel to the firstsubstrate 20 and the second substrate 30. Such behavior is due to thedielectric constant of the long axis being smaller than the short axisin the liquid crystal molecules 41A. Since the liquid crystal molecules41B and 41C have the same property, the liquid crystal molecules 41B and41C in essence exhibit the same behavior as the liquid crystal molecules41A according to changes in the ON and OFF states of the drivingvoltage. Here, when the driving voltage is in an OFF state, the firstpretilt angle θ₁ is conferred on the liquid crystal molecules 41A by thefirst alignment film 22, and the directors thereof have an inclinedstance from the normal vector direction of the first substrate 20 andthe second substrate 30. On the other hand, although the second pretiltangle θ₂ is conferred on the liquid crystal molecules 41B by the secondalignment film 32, the directors thereof are parallel to the normalvector direction of the second substrate 30 or alternatively have aninclined stance from the normal vector direction of the first substrate20 and the second substrate 30. Here, “maintained” refers to regulatingthe alignment of the liquid crystal molecules 41 without the alignmentfilms 22 and 32 and the liquid crystal molecules 41A and 41B being fixedtogether. Further, as illustrated in FIG. 3, in a case when a directionthat is vertical to the surfaces of the first substrate 20 and thesecond substrate 30 (normal vector direction) is Z, “pretilt angle θ(θ₁, θ₂)” refers to the inclination angle of directors D of the liquidcrystal molecules 41 (41A, 41B) with respect to the Z direction when thedriving voltage is in an OFF state.

Next, while a manufacturing method of the liquid crystal display device(liquid crystal display element) described above will be described, sucha manufacturing method includes: performing formation and processing ofa first alignment film 22 composed of a polymer compound (pre-alignmentprocess compound) that includes a cross-sectional functional group or apolymerized functional group as a side chain on one of a pair ofsubstrates 20 and (specifically, the substrate 20) and performingformation and processing of a second alignment film 32 composed of thesame polymer compound (pre-alignment process compound) as the polymercompound that configures the first alignment film 22 on the other of thepair of substrates 20 and 30 (specifically, the substrate 30); arrangingthe pair of substrates 20 and 30 so that the first alignment film 22 andthe second alignment film 32 are opposing and sealing a liquid crystallayer 40 that includes liquid crystal molecules 41 with negativedielectric constant anisotropy between the first alignment film 22 andthe second alignment film 32; and conferring a pretilt on the liquidcrystal molecules 41 by cross-linking or polymerizing the polymercompound (pre-alignment process compound. Alternatively, themanufacturing method of the liquid crystal display device includes:performing formation and processing of the first alignment film 22composed of a polymer compound (pre-alignment process compound) thatincludes a cross-linked functional group or a photosensitive functionalgroup as a side chain on one of a pair of substrates 20 and 30(specifically, the substrate 20) and performing formation and processingof the second alignment film 32 composed of the same polymer compound asthe polymer compound that configures the first alignment film 22(pre-alignment process compound) on the other of the pair of substrates20 and 30 (specifically, the substrate 30); arranging the pair ofsubstrates 20 and 30 so that the first alignment film 22 and the secondalignment film 32 are opposing and sealing a liquid crystal layer 40that includes liquid crystal molecules 41 with negative dielectricconstant anisotropy between the first alignment film 22 and the secondalignment film 32; and conferring a pretilt on the liquid crystalmolecules 41 by irradiating the polymer compound (pre-alignment processcompound) with energy rays.

First, formation and processing of the first alignment film 22 isperformed on the surface of the first substrate (TFT substrate) 20, andformation and processing of the second alignment film 32 is performed onthe surface of the second substrate (CF substrate) 30.

Specifically, first, the TFT substrate 20 is produced by providing thepixel electrodes 20B on the first substrate 20 in a matrix shape.Further, the CF substrate 30 is produced by providing the opposingelectrodes 30B on the color filter of the second substrate 30 on which acolor filter is provided.

On the other hand, a liquid alignment film material for the firstalignment film and the second alignment film is prepared by mixing, forexample, the pre-alignment process compound or a polymer compoundprecursor as the pre-alignment process compound, a solvent, and avertical alignment agent as necessary.

In a case when the polymer compound that includes a cross-linkedfunctional group or a polymerized functional group as the side chain,for example, includes the polyimide structure shown in Formula 3 as thepolymer compound precursor as the pre-alignment process compound,polyamic acid that includes a cross-linked functional group or apolymerized functional group is exemplified. The polyamic acid as thepolymer compound precursor is synthesized by reacting a diamine compoundwith a tetracarboxylic dianhydride, for example. At least one of thediamine compound and the tetracarboxylic dianhydride used here includesa cross-linked functional group or a polymerized functional group. Asthe diamine compound, for example, the compounds including across-linked functional group or a polymerized functional grouprepresented in Formulae A-1 to A-21 are exemplified, and as thetetracarboxylic dianhydride, the compounds including a cross-linkedfunctional group or a polymerized functional group represented byFormulae a-1 to a-10 are exemplified. Here, the compounds represented byFormulae A-9 to A-21 are compounds that configure the cross-linkedportions of the cross-linked polymer compound and the terminal structureportion according to the 1C configuration of the present disclosure.Alternatively, the compounds represented by Formulae F-1 to F-22 areexemplified as the compound that configures the cross-linked portions ofthe cross-linked polymer compound and the terminal structure portionaccording to the 1C configuration of the present disclosure. Here, withregard to the compounds represented by Formulae F-1 to F-18, it isconsidered that a pretilt is conferred on the liquid crystal moleculesalong the terminal structure portions of the compounds represented byFormulae F-1 to F-3, Formulae F-7 to F-9, and Formulae F-13 to F-15, andon the other hand, it is considered that a pretilt is conferred on theliquid crystal molecules by being interposed by the terminal structureportions of the compounds represented by Formulae F-4 to F-6, FormulaeF-10 to F-12, and Formulae F-16 to F-18. Further, it is presumed that apretilt is conferred on the liquid crystal molecules along the terminalstructure portions of the compounds represented by Formulae F-19 toF-22, or alternatively that a pretilt is conferred on the liquid crystalmolecules by being interposed between the terminal structure portions ofthe compounds represented by Formulae F-19 to F-22.

Here, X1 to X4 are single-bond or divalent organic groups.

Here, X5 to X7 are single-bond or divalent organic groups.

Further, in a case when polyamic acid is synthesized as the polymercompound precursor so that the pre-alignment process compound includes avertical alignment inducing structure portion, other than the compoundincluding a cross-linked functional group or a polymerized functionalgroup described above, the compounds including a vertical alignmentinducing structure portion represented by Formulae B-1 to B-36 asdiamine compounds or the compounds including a vertical alignmentinducing structure portion represented by Formulae b-1 to b-3 as atetracarboxylic dianhydride may be used.

Here, a4 to a6 are integers from 0 to 21.

Here, a4 is an integer from 0 to 21.

Here, a4 is an integer from 0 to 21.

Further, in a case when polyamic acid is synthesized as the polymercompound precursor so that the pre-alignment process compound includesthe group shown in Formula 1 along with a cross-linked functional groupor a polymerized functional group, other than the compound including across-linked functional group or a polymerized functional groupdescribed above, compounds that include groups that are able to be alongthe liquid crystal molecules 41 represented by Formulae C-1 to C-24 maybe used as diamine compounds.

Further, in a case when polyamic acid is synthesized as the polymercompound precursor so that the pre-alignment process compound includesthe group shown in Formula 2, other than the compound including across-linked functional group or a polymerized functional groupdescribed above, compounds that include groups that are able to be alongthe liquid crystal molecules 41 represented by Formulae D-1 to D-11 maybe used as diamine compounds.

Here, n is an integer from 3 to 20.

Furthermore, in a case when polyamic acid is synthesized as the polymercompound precursor so that the pre-alignment process compound includesthe two structures of a structure that includes a vertical alignmentinducing structure portion as R2 in Formula 3 and a structure thatincludes a cross-linked functional group or a polymerized functionalgroup, for example, the diamine compound and the tetracarboxylicdianhydride are selected as follows. That is, at least one of thecompounds including a cross-linked functional group or a polymerizedfunctional group shown in Formulae A-1 to A-21, at least one of thecompounds including the vertical alignment inducing structure portionshown in Formulae B-1 to B-36 and b-1 to b-3, and at least one of thetetracarboxylic dianhydrides represented by Formulae E-1 to E-28 areused. Here, R1 and R2 in Formula E-23 have the same or different alkylgroups, alkoxy groups, and halogen atoms, and the type of halogen atomsis arbitrary.

Here, R1 and R2 are alkyl groups, alkoxy groups, or halogen atoms.

Further, in a case when polyamic acid is synthesized as the polymercompound precursor so that the pre-alignment process compound includesthe two structures of a structure that includes the group shown inFormula 1 as R2 in Formula 3 and a structure that includes across-linked functional group or a polymerized functional group, forexample, the diamine compound and the tetracarboxylic dianhydride areselected as follows. That is, at least one of the compounds including across-linked functional group or a polymerized functional group shown inFormulae A-1 to A-21, at least one of the compounds shown in FormulaeC-1 to C-24, and at least one of the tetracarboxylic dianhydridesrepresented by Formulae E-1 to E-28 are used.

Further, in a case when polyamic acid is synthesized as the polymercompound precursor so that the pre-alignment process compound includesthe two structures of a structure that includes the group shown inFormula 2 as R2 in Formula 3 and a structure that includes across-linked functional group or a polymerized functional group, forexample, the diamine compound and the tetracarboxylic dianhydride areselected as follows. That is, at least one of the compounds including across-linked functional group or a polymerized functional group shown inFormulae A-1 to A-21, at least one of the compounds shown in FormulaeD-1 to D-11, and at least one of the tetracarboxylic dianhydridesrepresented by Formulae E-1 to E-28 are used.

The content amount of the pre-alignment process compound or the polymercompound precursor as the pre-alignment process compound within thealignment film material is preferably 1 mass % to 30 mass %, and morepreferably 3 mass % to 10 mass %. Further, a photopolymerizationinitiator or the like may be mixed with the alignment film material asnecessary.

Furthermore, the formation and processing of the first alignment film 22on the TFT substrate 20 is performed, and the formation and processingof the second alignment film 32 on the CF substrate 30 is performed.Specifically, after respectively applying or printing the preparedalignment film material on the TFT substrate 20 and the CF substrate 30to cover the pixel electrodes 20B and the opposing electrodes 30B, aheating process (predrying and calcination) is performed. Thetemperature of the heating process is preferably equal to or greaterthan 80° C., and is more preferably equal to or greater than 150° C. andequal to or less than 200° C. Further, the heating temperature of theheating process may be changed in a stepwise manner. In so doing, thesolvent included in the applied or printed alignment film materialevaporates and the alignment films 22 and 32 that include the polymercompound (pre-alignment process compound) including a cross-linkedfunctional group or a polymerized functional group as the side chain areformed. Processing (specifically, a rubbing process) is then performedon the first alignment film 22 and the second alignment film 32. Morespecifically, a mask layer with an opening portion on the firstalignment film 22 and the second alignment film 32 is formed, and arubbing process is performed on the first alignment film 22 and thesecond alignment film 32 that are exposed at the bottom portion of theopening portion. By repeating such a process M times (for example, twiceor four times), it is possible to obtain a first alignment film 22 and asecond alignment film 32 with M directions (for example, two directionsor four directions) as rubbing directions. Here, the formation andprocessing of the second alignment film 32 is different from theformation and processing of the first alignment film 22. Specifically,the strength of pressure of the rubbing roller against the alignmentfilms during the rubbing process is weak against the second alignmentfilm 32 and strong against the first alignment film 22. Alternatively,while a rubbing process is performed on the first alignment film 22, arubbing process is not performed on the second alignment film 32.

Here, the pre-alignment process compound within the alignment films 22and 32 is considered to be in the state illustrated in FIG. 4. That is,the pre-alignment process compound is configured to include main chainsMc (Mc1 to Mc3) and a cross-liked functional group A or a polymerizedfunctional group A that is introduced to the main chains Mc as a sidechain, and the main chains Mc1 to Mc3 exist in a coupled state. Thecross-linked functional group A and the polymerized functional group Ain such a state are orientated in a random direction by thermalagitation.

Next, the TFT substrate 20 and the CF substrate 30 are arranged so thatthe first alignment film 22 and the second alignment film 32 areopposing, and the liquid crystal layer 40 including the liquid crystalmolecules 41 is sealed between the first alignment film 22 and thesecond alignment film 32. Specifically, spacer protrusions, for example,plastic beads and the like for securing a cell gap are scattered and aseal portion is printed using an epoxy adhesive or the like by a screenprinting method, for example, on a face on which the alignment films 22and 32 are formed on either the TFT substrate 20 or the CF substrate 30.As illustrated in FIG. 1, the TFT substrate 20 and the CF substrate 30are adhered together via the spacer protrusions and the seal portion sothat the alignment films 22 and 32 are opposing, and the liquid crystalmaterial that includes the liquid crystal molecules 41 is pouredtherein. Next, by performing curing of the seal portion by heating andthe like, the liquid crystal material is sealed between the TFTsubstrate 20 and the CF substrate 30.

Furthermore, the alignment films 22 and 32 are irradiated with energyrays (specifically, ultraviolet radiation) from the outside of the TFTsubstrate 20, for example. That is, the ultraviolet radiation isirradiated so that the liquid crystal molecules 41A are aligned in adiagonal direction with respect to the surface of the substrate 20. Inso doing, the cross-linked functional group or polymerized functionalgroup included in the pre-alignment process compound within thealignment films 22 and 32 is reacted, and the pre-alignment processcompound is cross-linked. In such a manner, the direction in which thelight crystal molecules 41 are to react is stored by the post-alignmentprocess compound, a pretilt is conferred on the liquid crystal molecules41A in the vicinity of the first alignment film 22, and the liquidcrystal molecules 41B in the vicinity of the second alignment film 32are vertically aligned or aligned by a small pretilt angle. Furthermore,as a result, the post-alignment process compound is formed within thealignment films 22 and 32, and since the formation and processing of thesecond alignment film 32 is different from the formation and processingof the first alignment film 22 in a non-driving state, the first pretiltangle θ₁ is conferred on the liquid crystal molecules 41A positioned inthe vicinity of the interface of the liquid crystal layer 40 with thefirst alignment film 22 and the second pretilt angle θ₂ (<θ₁) isconferred on the liquid crystal molecules 41B positioned in the vicinityof the interface with the second alignment film 32. Ultravioletradiation that includes many optical components with wavelengths ofapproximately 295 nm to 365 nm is preferable as the ultravioletradiation UV. The reason is that if ultraviolet radiation including manyoptical components with shorter wavelengths is used, there is a concernthat the liquid crystal molecules 41 may photodegrade and deteriorate.Here, although the ultraviolet radiation UV is irradiated from theoutside of the TFT substrate 20, the ultraviolet radiation UV may beirradiated from the outside of the CF substrate 30 and may be irradiatedfrom the outside of both the TFT substrate 20 and the CF substrate 30.In such a case, it is preferable that the ultraviolet radiation UV beirradiated from the side of the substrate with higher transmittance.Further, in a case when the ultraviolet radiation UV is irradiated fromthe outside of the CF substrate 30, depending on the wavelength of theultraviolet radiation UV, there is a concern that the ultravioletradiation UV may be absorbed by the color filter, making cross-linkingreaction difficult. It is therefore preferable that the ultravioletradiation UV be irradiated from the outside of the TFT substrate 20(side of the substrate with pixel electrodes).

Here, the post-alignment process compound within the alignment films 22and 32 is in the state illustrated in FIG. 5. That is, the orientationof the cross-linked functional group A or the polymerized functionalgroup A introduced to the main chains Mc of the pre-alignment processcompound changes according to the alignment direction of the liquidcrystal molecules 41, and a coupled portion Cr is formed by thecross-linked functional groups A or the polymerized functional groups Athat are physically close together reacting with each other. It isconsidered that the alignment films 22 and 32 confer the first pretiltangle θ₁ and the second pretilt angle θ₂ on the liquid crystal molecules41A and 41B by the post-alignment process compound generated in such amanner. Here, the coupled portion Cr may be formed between pre-alignmentprocess compounds or may be formed within the pre-alignment processcompounds. That is, as illustrated in FIG. 5, the coupled portion Cr maybe formed by reaction between the cross-linked functional groups A orthe polymerized functional groups A of a pre-alignment process compoundthat includes the main chain Mc1, for example, and the cross-linkedfunctional groups A or the polymerized functional groups A of apre-alignment process compound that includes the main chain Mc2.Further, as with a polymer compound that includes a main chain Mc3, forexample, the coupled portion Cr may be formed by the cross-linkedfunctional group A or the polymerized functional group A introduced tothe same main chain Mc3 reacting with each other. Here, in the case of apolymerized functional group, a plurality of polymerized functionalgroups A are coupled.

The liquid crystal display device (liquid crystal display element)illustrated in FIG. 1 is able to be completed by the processes describedabove.

According to the actions of the liquid crystal display device (liquidcrystal display element), if a driving voltage is applied to selectedpixels 10, the alignment state of the liquid crystal molecules 41included in the liquid crystal layer 40 changes according to thepotential difference between the pixel electrodes 20B and the opposingelectrodes 30B. Specifically, in the liquid crystal layer 40, from thestate before the driving voltage is applied illustrated in FIG. 1, theliquid crystal molecules 41A and 41B that are positioned in the vicinityof the alignment films 22 and 32 fall in the tilting direction thereofby the driving voltage being applied, and such an action is propagatedto the other liquid crystal molecules 41C. As a result, the liquidcrystal molecules 41 react by adopting a posture that is approximatelyhorizontal (parallel) to the TFT substrate 20 and the CG substrate 30.In so doing, an image is displayed by the optical characteristics of theliquid crystal layer 40 changing, the incident light on the liquidcrystal display element becoming modulated outgoing light, and thegradation being expressed by such outgoing light.

Here, with a liquid crystal display element in which a pretilt processhas not been carried out at all or a liquid crystal display deviceincluding such an element, when a driving voltage is applied, withliquid crystal molecules that are aligned in the vertical direction withrespect to the substrates, the directors thereof fall with an arbitraryorientation in an in-plane direction of the substrates. With liquidcrystal molecules that react to the driving voltage in such a manner,the orientation of the director of each liquid crystal molecule becomesblurred, and the overall alignment becomes disturbed. Accordingly, thereis a problem that the response speed (startup speed of the imagedisplay) becomes slow, the response characteristics deteriorate, and asa result, the display characteristics decline. Further, if the initialdriving voltage is set higher than the driving voltage in the displaystate and driven (overdriving), there are liquid crystal molecules thatrespond and liquid crystal molecules that hardly respond, and a largedifference in the inclinations of the directors emerge therebetween. Ifthe driving voltage of the display state is then applied, the liquidcrystal molecules that responded when the initial driving voltage wasapplied adopt the inclinations of the directors according to the drivingvoltage of the display state while the actions thereof are hardlypropagated to the other liquid crystal display molecules, and suchinclinations are propagated to the other liquid crystal molecules. As aresult, although the pixels as a whole reach the brightness of thedisplay state when the initial driving voltage is applied, thebrightness then decreases before once again reaching the brightness ofthe display state. That is, with overdriving, although the responsespeed seemingly becomes faster than in a case when overdriving is notperformed, there is a problem that it is difficult to obtain asufficient display quality. Here, such problems rarely occur with an IPSmode or FFS mode liquid crystal display element, and it is consideredthat such a problem is unique to a VA mode liquid crystal displayelement.

On the other hand, with the liquid crystal display device (liquidcrystal display element) of Embodiment 1 and the manufacturing methodthereof, the first alignment film 22 and the second alignment film 32confer the predetermined first pretilt angle θ₁ and the second pretiltangle θ₂ on the liquid crystal molecules 41A and 41B. In so doing, theproblem of a case when a pretilt process is not carried out at all doesnot easily occur, the response speed (startup speed of the imagedisplay) to the driving voltage improves greatly, and the displayquality from overdriving also improves. Moreover, the formation andprocessing of the second alignment film 32 is different from theformation and processing of the first alignment film 22, and as aresult, θ₁>θ₂. Therefore, not only the startup speed of the imagedisplay but also the termination speed is able to be improved. Further,since the liquid crystal molecules have the second pretilt angle θ₂ bythe second alignment film 32, the amount of light transmission duringblack display is able to be decreased, and the contrast is able to beimproved further.

Further, since the pre-alignment process compound within the alignmentfilms 22 and 32 is cross-linked or polymerized after the liquid crystallayer 40 is sealed between the alignment films 22 and 32, it is possibleto change the transmittance of the liquid crystal display element duringdriving to increase continuously.

Furthermore, in Embodiment 1 where a pretilt process is carried out bythe cross-linking reaction of the pre-alignment process compound afterthe liquid crystal layer 40 is sealed, the formation and processing ofthe alignment films is performed. Therefore, as illustrated in FIG. 7,since the direction of the pretilt of the liquid crystal molecules 41 iseasily coordinated, the order parameter increases (becomes closer to 1).Accordingly, since the liquid crystal molecules 41 exhibit even behaviorwhen the liquid crystal display element is driven, the transmittanceincreases continuously.

In such a case, in particular, if the pre-alignment process compoundincludes the group shown in Formula 1 along with a cross-linkedfunctional group or a polymerized functional group or the pre-alignmentprocess compound includes the group shown in Formula 2 as a cross-linkedfunctional group or a polymerized functional group, it becomes easier toconfer the pretilt angles θ₁ and θ₂ on the first alignment film 22 andthe second alignment film 32. It is therefore possible to furtherincrease the response speed (startup speed of the image display).

With Embodiment 1, although a case when the alignment films 22 and 32that include a pre-alignment process compound that includes a main chainincluding a polyimide structure are used has been mainly described, themain chain that the pre-alignment process compound includes is notlimited to those including a polyimide structure. For example, the mainchain may include a polysiloxane structure, a polyacrylate structure, apolymethacrylate structure, a maleimide polymer structure, a styrenepolymer structure, a styrene/maleimide polymer structure, apolysaccharide structure, a polyvinyl alcohol structure, and the like,of which a pre-alignment process compound that includes a main chainincluding a polysiloxane structure is preferable. The reason is thateffects similar to a polymer compound that includes a polysiloxanestructure are then obtained. A polymer compound that includes thepolysiloxane structure represented by FIG. 9, for example, isexemplified as a pre-alignment process compound that includes a mainchain including a polysiloxane structure. Although R10 and R11 inFormula 9 are arbitrary as long as R10 and R11 are monovalent andconfigured to include carbon atoms, it is preferable that a cross-linkedfunctional group or a polymerized functional group as a side chain and aside chain composed of Formula 1 be included in either R10 or R11. Thereason is that it is then easy to obtain sufficient alignment regulatingcapabilities with the post-alignment process compound. The group shownin Formula 41 above and the like are exemplified as the cross-linkedfunctional group or the polymerized functional group in such a case.

Here, R10 and R11 are monovalent organic groups, and m1 is an integerequal to or greater than 1.

Here, in the example illustrated in FIG. 1, although the first alignmentfilm 22 that covers the TFT substrate that is the first substrate 20 hasa configuration of conferring the first pretilt angle θ₁ on the liquidcrystal molecules 41A that are positioned on the side of the firstsubstrate (TFT substrate) 20, the configuration is not limited thereto.That is, as illustrated in FIG. 2, it is also possible for the firstsubstrate 20 to be the CF substrate and for the second substrate 30 tobe the TFT substrate, and even in such a case, it is possible to obtainthe same effects as the liquid crystal display device illustrated inFIG. 1. However, with the TFT substrate, since various transverseelectric fields are generated when driving, it is desirable that themodification of the liquid crystal display device of FIG. 2 in which thesecond substrate 30 is the TFT substrate be adopted. In so doing, it ispossible to effectively reduce alignment disturbance of the liquidcrystal molecules 41 by transverse electric fields.

Next, although other embodiments will be described, description forconstituent elements that are in common with Embodiment 1 will beomitted by using the same reference symbols. Further, the same actionsand effects as Embodiment 1 will also be omitted as appropriate.Furthermore, the various technical items described above according toEmbodiment 1 are also applied to the embodiments below as appropriate.

Embodiment 2

Embodiment 2 is a modification of Embodiment 1. With the liquid crystaldisplay device of Embodiment 2, first alignment regulating portions 21are provided on first electrodes (pixel electrodes) 20B, and the firstalignment film 22 covers the first electrodes (pixel electrodes) 20B,the first alignment regulating portions 21, and the opposing face of thefirst substrate (TFT substrate) 20. A schematic partial cross-sectionaldiagram of the liquid crystal display device of Embodiment 2 of thepresent disclosure is illustrated in FIG. 8.

More specifically, first slit portions 21 (portion on which an electrodeis not formed) with a striped or V-shaped pattern, for example, areprovided within each pixel of the pixel electrodes 20B. Here, anarrangement diagram of a first electrode (pixel electrode) 20B and firstslit portions 21 when a pixel (subpixel) is viewed from above isillustrated in FIG. 10A or 10B. In so doing, when a driving voltage isapplied, since an electric field that is diagonal with respect to thelong axis direction of the liquid crystal molecules 41 is conferred andregions with different alignment directions are formed within the pixels(alignment demarcation), the viewing angle characteristics are improved.That is, the second slit portions 31 are the second alignment regulatingportions for regulating the entirety of the liquid crystal molecules 41within the liquid crystal layer 40 for securing favorable displaycharacteristics, and here, the alignment direction of the liquid crystalmolecules 41 when a driving voltage is applied is regulated by the firstslit portions 21. In essence, the azimuth angle of the liquid crystalmolecules when a pretilt is conferred is regulated by the strength anddirection of the electric field and the molecular structure of thealignment film material, and the direction of the electric field isdetermined by the alignment regulating portions. The width of the firstslit portions 21 is 5 μm and the pitch of the first slit portions 21 is113 μm.

Furthermore, the side chain of the polymer compound (pre-alignmentprocess compound) is cross-linked or polymerized by irradiating energyrays (specifically, ultraviolet radiation UV) on the polymer compound(pre-alignment process compound) or heating the polymer compound whilealigning the liquid crystal molecules 41 by applying a predeterminedelectric field (or magnetic field) on the liquid crystal layer 40.

A manufacturing method of the liquid crystal display device ofEmbodiment 2 will be described below with reference to the flowchart ofFIG. 11 along with the schematic partial cross-sectional diagrams of theliquid crystal display device and the like illustrated in FIGS. 12 to14. Here, in FIGS. 12 to 14, only one pixel is shown for simplicity.

Specifically, first, the TFT substrate 20 is produced by providing thepixel electrodes 20B that includes the predetermined first slit portions21 on the surface of the first substrate 20 in a matrix shape, forexample. Further, the CF substrate 30 is produced by providing theopposing electrodes 30B on the color filter of the second substrate 30on which a color filter is formed. On the other hand, a liquid alignmentfilm material for the first alignment film and the second alignment filmis prepared in the same manner as Embodiment 1. Furthermore, similarlyto Embodiment 1, the formation and processing of the first alignmentfilm 22 on the surface of the first substrate (TFT substrate) 20 isperformed, and the formation and processing of the second alignment film32 on the surface of the second substrate (CF substrate) 30 is performed(step S101).

Next, similarly to FIG. 1, the TFT substrate 20 and the CF substrate 30are arranged so that the first alignment film 22 and the secondalignment film 32 are opposing, and the liquid crystal layer 40 thatincludes the liquid crystal molecules 41 is sealed between the firstalignment film 22 and the second alignment film 32 (step S102). Asillustrated in FIG. 12, the TFT substrate 20 and the CF substrate 30 arethen adhered together via the spacer protrusions and the seal portion sothat the alignment films 22 and 32 are opposing, and the liquid crystalmaterial that includes the liquid crystal molecules 41 is poured in.Next, by performing curing of the seal portion by heating and the like,the liquid crystal material is sealed between the TFT substrate 20 andthe CF substrate 30.

Next, as illustrated in FIG. 13, a voltage V1 is applied between thepixel electrodes 20B and the opposing electrodes 30B using a voltageapplying section (step S103). The voltage V1 is, for example, 3 volts to30 volts. In so doing, an electric field in a direction with apredetermined angle with respect to the surfaces of the first substrate20 and the second substrate 30 is generated, and the liquid crystalmolecules 41A are aligned with a tilt toward a predetermined directionfrom the vertical direction of the first substrate 20. Further, theliquid crystal molecules 41B are aligned in a direction that is, forexample, parallel to the vertical direction of the second substrate 30,or alternatively, are aligned titled in a predetermined direction fromthe vertical direction of the second substrate 30. That is, the azimuthangle (angle of deviation) of the liquid crystal molecules 41 at thistime is regulated by the strength and the direction of the electricfield and the molecular structure of the alignment film material, andthe polar angle (zenith angle) is regulated by the strength of theelectric field and the molecular structure of the alignment filmmaterial. Furthermore, the inclination angle of the liquid crystalmolecules 41 and the first pretilt angle θ₁ and the second pretilt angleθ₂ that are conferred on the liquid crystal molecules 41A that aremaintained by the first alignment film 22 in the vicinity of theinterface with the first alignment film 22 and on the liquid crystalmolecules 41B that are maintained by the second alignment film 32 in thevicinity of the interface with the second alignment film 32 satisfyθ₁>θ₂ due to the difference in the formation and processing between thefirst alignment film 22 and the second alignment film 32. Furthermore,it is possible to control the values of the first pretilt angle θ₁ andthe second pretilt angle θ₂ of the liquid crystal molecules 41A and 41Bby adjusting the value of the voltage V1 as appropriate.

In addition, as illustrated in FIG. 14, the alignment films 22 and 32are irradiated with energy rays (specifically, ultraviolet radiation UV)from the outside of the TFT substrate 20, for example, while the voltageV1 is still applied. That is, ultraviolet radiation is irradiated whilean electric field or a magnetic field is applied to the liquid crystallayer so that the liquid crystal molecules 41A are arranged in adiagonal direction with respect to the surface of the substrate 20. Inso doing, the cross-linked functional group or the polymerizedfunctional group of the pre-alignment process compound within thealignment films 22 and 32 are reacted, and the pre-alignment processcompound is cross-linked (step S104). In such a manner, the direction inwhich the light crystal molecules 41 are to react is stored by thepost-alignment process compound, a pretilt is conferred on the liquidcrystal molecules 41A in the vicinity of the first alignment film 22,and the liquid crystal molecules 41B in the vicinity of the secondalignment film 32 are vertically aligned or aligned by a small pretiltangle. As a result, the post-alignment process compound is formed withinthe alignment films 22 and 32, the first pretilt angle θ₁ is conferredon the liquid crystal molecules 41A positioned in the vicinity of theinterface with the first alignment film 22 in the liquid crystal layer40, and the second pretilt angle θ₂ (<θ₁) is conferred on the liquidcrystal molecules 41B positioned in the vicinity of the interface withthe second alignment film 32.

By the processes above, the liquid crystal display device (liquidcrystal display element) illustrated in FIG. 8 is able to be completed.

Here, in Embodiment 2, since the first slit portions 21 as the alignmentregulating portions for regulating the alignment of the liquid crystalmolecules 41 are provided on the TFT substrate 20 and displaycharacteristics such as the viewing angle characteristics are secured,the response characteristics are improved while maintaining favorabledisplay characteristics.

Further, with the manufacturing method of the liquid crystal displaydevice of the related art (light alignment technique), alignment filmsare formed to irradiate linearly polarized light and light in a diagonaldirection with respect to the substrate faces (hereinafter referred toas “diagonal light”) with respect to precursors including apredetermined polymer material provided on the substrate faces, carryingout a pretilt process therewith. There is therefore a problem that anextensive light irradiation device that irradiates linearly polarizedparallel light is demanded. In particular, in a case when formingalignment films using diagonal light, if there are structures such asspacers and unevenness on the substrates, regions where the light doesnot reach in the shadows of the structures and the like appear, and thedesirable alignment regulation of the liquid crystal molecules in suchregions becomes difficult. In such a case, for example, in order toirradiate diagonal light using a photomask for providing a multi-domainwithin the pixels, a pixel setting taking the diffraction of light intoconsideration becomes important. That is, in a case when formingalignment films using diagonal light, there is also a problem that theformation of high definition pixels is difficult.

Furthermore, out of the light alignment techniques of the related art,in a case when a cross-linked polymer compound is used as the polymermaterial, since the cross-linked functional group or the polymerizedfunctional group included in the cross-linked functional group withinthe precursor film has a random orientation (direction) by thermalagitation, the probability of the physical distances between thecross-linked functional groups and the polymerized functional groupsdecreasing becomes low. Moreover, in a case when random light(unpolarized light) is irradiated, although the cross-linked functionalgroups or the polymerized functional groups react by the physicaldistances therebetween decreasing, it is important for the polarizingdirection and the direction of the reacting portions of the cross-linkedfunctional groups or the polarized functional groups that react byirradiating linearly polarized light match a predetermined direction.Further, with diagonal light, compared to vertical light, the greaterthe irradiation area becomes, the more the irradiation amount per unitarea decreases. That is, the proportion of the cross-linked functionalgroup or the polarized functional group that react to linearly polarizedlight or diagonal light decreases compared to a case when the substratefaces are irradiated by random light (unpolarized light) from thevertical direction. Accordingly, the cross-linking density (degree ofcross-linking) within the alignment films that are formed tends todecrease.

On the other hand, in Embodiment 2, the liquid crystal layer 40 issealed between the first alignment film 22 and the second alignment film32 after the alignment films 22 and 32 that include the pre-alignmentprocess compound are formed. Next, the liquid crystal molecules 41 adopta predetermined alignment by a voltage being applied on the liquidcrystal layer 40, and the pre-alignment process compound within thealignment films 22 and 32 is cross-linked or polymerized while thedirections of the terminal structure portions of the side chains withrespect to the substrates or the electrodes are regulated by the liquidcrystal molecules 41. That is, a pretilt is conferred according to thealignment direction of the liquid crystal molecules 41 during driving bythe first slit portions 21 for regulating the alignment of the liquidcrystal molecules 41 in the vicinity of the first alignment film 22. Inso doing, it is possible to form the first alignment film 22 and thesecond alignment film 32 that confer the first pretilt angle θ₁ and thesecond pretilt angle θ₂ on the liquid crystal molecules 41A and 41B.That is, according to the liquid crystal display device (liquid crystaldisplay element) and the manufacturing method thereof of Embodiment 2,the response characteristics are easily able to be improved withoutusing an extensive device. Moreover, since it is possible to confer thefirst pretilt angle θ₁ on the liquid crystal molecules 41 without beingdependent on the irradiation direction of the ultraviolet radiation whenthe pre-alignment process compound is cross-linked or polymerized, it ispossible to form high definition pixels. Furthermore, since thepost-alignment process compound is generated in a state in which theorientations of the terminal structure portions of the side chains areordered in the pre-alignment process compound, it is considered that thedegree of cross-linking in the post-alignment process compound isgreater than with the alignment films of the manufacturing method of therelated art described above. Therefore, since cross-linked structurestend not to be newly created during driving even after driving for anextended period of time and the pretilt angles θ₁ and θ₂ of the liquidcrystal molecules 41A and 41B are maintained at the same state as at thetime of manufacture, reliability is also able to be improved.

Furthermore, although the viewing angle characteristics were to beimproved by providing the first slit portions 21 in Embodiment 2,improving the viewing angle characteristics is not limited thereto. Forexample, protrusions as alignment regulating portions may be providedover the pixel electrodes 20B instead of the first slit portions 21. Byproviding protrusions in such a manner, the same effects as in a casewhen the first slit portions 21 are provided are obtained.

Here, although the first alignment film 22 that covers the TFT substratethat is the first substrate 20 has a configuration of conferring thefirst pretilt angle θ₁ on the liquid crystal molecules 41A positioned onthe side of the first substrate (TFT substrate) 20 in the exampleillustrated in FIG. 8, the embodiments of the present disclosure are notlimited to such a configuration. That is, as illustrated in FIG. 9, itis possible for the first substrate 20 to be the CF substrate and forthe second substrate 30 to be the TFT substrate, and in such a case, itis still possible to obtain the same effects as the liquid crystaldisplay device illustrated in FIG. 8.

Embodiment 3

Embodiment 3 relates to the liquid crystal display device according tothe second embodiment of the present disclosure, and to themanufacturing methods of the liquid crystal display devices according tothe second and third embodiments of the present disclosure.

In Embodiment 1, the post-alignment process compound is obtained by thecross-linked functional group or the polymerized functional group in apre-alignment process compound that includes a cross-linked functionalgroup or a polymerized functional group as a side chain beingcross-linked or polymerized. On the other hand, in Embodiment 3, thefirst alignment film 22 includes a compound (post-alignment process) inwhich a polymer compound that includes a photosensitive functional groupas a side chain is deformed, the second alignment film 32 includes thesame compound (post-alignment process compound) as the compound(post-alignment process compound) that configures the first alignmentfilm 22, and the formation and processing of the second alignment film32 is different from the formation and processing of the first alignmentfilm 22, and when the pretilt angle of the liquid crystal molecules 41which is conferred by the first alignment film 22 (that is, by thepost-alignment process compound) is θ₁ and the pretilt angle of theliquid crystal molecules 41 which is conferred by the second alignmentfilm 32 (that is, by the post-alignment process compound) is θ₂, therelationship θ₁>θ₂ is conferred. The post-alignment process compound isobtained based on a pre-alignment process compound that includes aphotosensitive functional group deformed by the irradiation of energyrays as a side chain.

Further, the manufacturing method of the liquid crystal display deviceof Embodiment 3 includes performing formation and processing of a firstalignment film 22 composed of a polymer compound (pre-alignment processcompound) that includes a cross-sectional functional group or apolymerized functional group as a side chain on one of a pair ofsubstrates 20 and 30 and performing formation and processing of a secondalignment film 32 composed of the same polymer compound (pre-alignmentprocess compound) as the polymer compound that configures the firstalignment film 22 on the other of the pair of substrates 20 and 30,arranging the pair of substrates 20 and 30 so that the first alignmentfilm 22 and the second alignment film 32 are opposing and sealing aliquid crystal layer 40 that includes liquid crystal molecules 41 withnegative dielectric constant anisotropy between the first alignment film22 and the second alignment film 32, and conferring a pretilt on theliquid crystal molecules 41 by cross-linking or polymerizing the polymercompound (pre-alignment process compound) (that is, conferring a pretilton the liquid crystal molecules 41 by the post-alignment processcompound), or alternatively, includes performing formation andprocessing of the first alignment film 22 composed of a polymer compound(pre-alignment process compound) that includes a cross-linked functionalgroup or a photosensitive functional group as a side chain on one of apair of substrates 20 and 30 and performing formation and processing ofthe second alignment film 32 composed of the same polymer compound asthe polymer compound that configures the first alignment film 22(pre-alignment process compound) on the other of the pair of substrates20 and 30, arranging the pair of substrates 20 and 30 so that the firstalignment film 22 and the second alignment film 32 are opposing andsealing a liquid crystal layer 40 that includes liquid crystal molecules41 with negative dielectric constant anisotropy between the firstalignment film 22 and the second alignment film 32, and conferring apretilt on the liquid crystal molecules 41 by irradiating the polymercompound (pre-alignment process compound) with energy rays (that is,conferring a pretilt on the liquid crystal molecules 41 by thepost-alignment process compound).

Herein, in Embodiment 3, the alignment films 22 and 32 are alsoconfigured to include one or two or more types of a polymer compound(post-alignment process compound) that includes a cross-linked structurein the side chain or to respectively include one or two or more types ofa side chain including a terminal group along the liquid crystals shownin Formula 1 along with a cross-linked functional group or a polymerizedfunctional group. Furthermore, a pretilt is conferred to the liquidcrystal molecules by a deformed compound. Here, after forming thealignment films 22 and 32 in a state of including one or two or moretypes of a polymer compound (pre-alignment process compound) including amain chain and a side chain, the post-alignment process compound isgenerated by providing the liquid crystal layer 40 and deforming thepolymer compound or alternatively by deforming the photosensitivefunctional group included in the side chain by irradiating the polymercompound with energy rays. Furthermore, similarly to Embodiment 1, sincea rubbing process is carried out on the alignment films 22 and 32, thepost-alignment process compound is able to arrange the liquid crystalmolecules in a predetermined direction (specifically, a diagonaldirection) with respect to one of the pair of substrates (the TFTsubstrate 20 or the CF substrate 30). In such a manner, since by thepost-alignment process compound being included within the alignmentfilms 22 and 32 by deforming the polymer compound or irradiating thepolymer compound with energy rays, a pretilt is able to be conferred onthe liquid crystal molecules 41 in the vicinity of the alignment films22 and 32, the response speed (startup speed and termination speed ofthe image display) becomes faster and the display characteristics areimproved.

An azobenzene compound including an azo group, a compound that includesimine and aldimine as the skeleton (for convenience, referred to as“aldimine benzene”), and a compound that includes a styrene skeleton(for convenience, referred to as “stilbene”) are exemplified as thephotosensitive functional group. Such compounds confer a pretilt on theliquid crystal molecules as a result of reacting to energy rays (forexample, ultraviolet radiation) and deforming, that is, as a result oftransitioning from a trans state to a cis state.

Formulae AZ-1 to AZ-9 below are specific examples of “X” in theazobenzene compound represented by Formula AZ-0.

Here, either one of R and R″ is bonded to a benzene ring that includesdiamine directly or via an ether, an ester, or the like, the otherbecomes a terminal group, R, R′, and R″ are monovalent group including ahydrogen atom, a halogen atom, an alkyl group, an alkoxy group, and acarbonate group or are derivatives thereof, and the terminal group mayinclude R2 of Formula 1 and R13 of Formula 2 therebetween. In so doing,a tilt is more easily able to be conferred. R″ is bonded to a benzenegroup that includes diamine directly or via an ether, an ester, or thelike.

Since the liquid crystal display device and the manufacturing methodthereof of Embodiment 3 is in essence the same as the liquid crystaldisplay device and the manufacturing method thereof described inEmbodiment 1 with the exception that a pre-alignment process compoundincluding a photosensitive functional group that is deformed by theirradiation of energy rays (specifically, ultraviolet radiation) isused, detailed description will be omitted.

Herein, the first slit portions 21 may be provided in Embodiment 3 inthe same manner as described in Embodiment 2. Further, thepost-alignment process compound is able to be generated by deforming theside chain of the polymer compound (pre-alignment process compound) byirradiating energy rays while deforming the polymer compound or aligningthe liquid crystal molecules 41 by applying a predetermined electricfield (or magnetic field) on the liquid crystal layer 40. Here, such astate is illustrated in the outline diagram of FIG. 16. Here, in FIG.16, the direction of the arrow with “UV” and the direction of the arrowwith “voltage” do not indicate the direction in which the ultravioletradiation is irradiated and the direction of the electric field that isapplied.

Example 1

Example 1 relates to the liquid crystal display device (liquid crystaldisplay element) according to the first embodiment of the presentdisclosure and the manufacturing method thereof and the liquid crystaldisplay device (liquid crystal display element) according to the thirdembodiment of the present disclosure and the manufacturing methodthereof. In Example 1, a modification of liquid crystal display device(liquid crystal display element) of Embodiment 1 illustrated in FIG. 2was produced by the following procedure.

First, the TFT substrate 20 and the CF substrate 30 were prepared. Asubstrate on which the pixel electrodes 20B composed of ITO thatincludes a slit pattern on one face side of a glass substrate 20A with athickness of 0.7 mm was used as the TFT substrate 20. Further, asubstrate on which the opposing electrodes 30B composed of ITO thatincludes a slit pattern on the color filter of a glass substrate 30Awith a thickness of 0.7 mm on which a color filter is formed was used asthe CF substrate 30.

On the other hand, the alignment film materials for the first and secondalignment films were prepared. In such a case, for example, first, thecompound including the cross-linked functional group shown in FormulaA-6, the compound including the vertical alignment inducing structureportion shown in Formula B-4, the tetracarboxylic dianhydride shown inFormula E-2, the compound represented by Formula G-1, and the diaminecompound represented by Formula C-1 were dissolved inN-methyl-2-pyrolidone (NMP). Next, after reacting the solvent for sixhours at 60° C., the reaction products were deposited by pouring in alarge excess of pure water. Subsequently, after separating and washingthe deposited solids with pure water, the solids were dried over fifteenhours at 40° C. at reduced pressure, and in so doing, the polyamic acid(refer to polymer compound 1 in Table 1) and the polyimide (refer topolymer compound 2 and polymer compound 3 in Table 1) that are thepolymer compound precursors as the pre-alignment process compound wereable to be synthesized. Finally, by dissolving 3.0 g of the obtainedpolyamic acid and polyimide in the NMP to produce a solution with asolid content concentration of 3 mass %, the solution was filtratedthrough a 0.2 μm filter. The alignment film material for forming thealignment films 22 and 32 were thereby obtained.

Next, after respectively applying and forming the prepared alignmentfilm material (refer to Table 1) on the TFT substrate 20 and the CFsubstrate 30 using a spin coater, the applied films were dried for 80seconds on an 80° C. hotplate. The TFT substrate 20 and the CF substrate30 were then heated for one hour in a 200° C. oven in an atmosphere ofnitrogen gas. In so doing, a CF substrate 30 in which the thickness ofthe first alignment film 22 on the pixel electrodes 20B is 90 nm and inwhich the thickness of the second alignment film 32 on the opposingelectrodes 30B is 90 nm was produced.

Processing (specifically, a rubbing process) was then performed on thefirst alignment film 22 and the second alignment film 32. Specifically,a mask layer with an opening on the first alignment film 22 and thesecond alignment film 32 was formed and a rubbing process was performedon the first alignment film 22 and the second alignment film 32 that areexposed to the bottom of the opening portion. In example 1, it waspossible to obtain a first alignment film 22 and a second alignment film32 with M directions (specifically, two directions) as rubbingdirections by repeating such a process M number of times (specifically,twice). Here, the formation and processing of the second alignment film32 is different from the formation and alignment of the first alignmentfilm 22. Specifically, the strength of pressure of the rubbing rolleragainst the alignment films during the rubbing process was weak againstthe second alignment film 32 and strong against the first alignment film22. Alternatively, while a rubbing process was performed on the firstalignment film 22, a rubbing process was not performed on the secondalignment film 32. Although the conditions for the rubbing process areshown in Table 2 below, the number of rotations of the rubbing rollerswas the same (500 rpm) for all conditions and the substrate feed ratewas also the same (20 mm per second) for all conditions.

TABLE 1 Compound including Compound for group able to be Cross-linkedmaterial vertical along liquid Tetracarboxylic Main chain (diaminecompound) alignment crystal molecules dianhydride spacer Polymer MolarMolar Molar Molar Molar compound Material Ratio Material ratio Materialratio Material ratio Material ratio 1 A-6 25 B-4 5 E-2 50 G-1 20 2 A-615 B-4 5 C-1 10 E-2 50 G-1 20 3 A-6 15 B-4 10 C-1 5 E-2 50 G-1 20

TABLE 2 Pressing amount of rubbing rollers Condition 1 0.3 mm Condition2 0.6 mm Condition 3 0.9 mm

Next, a seal portion was formed on the periphery of the pixel portionson the CF substrate 30 by applying an ultraviolet curable resinincluding silica particles with a particle diameter of 3.5 μm, and aliquid crystal material composed of MLC-7029 (manufactured by Merck &Co., Inc.) that is a negative type liquid crystal was poured dropwiseinto the portion surrounded by the seal portion. The TFT substrate 20and the CF substrate 30 were then adhered together and the seal portionwas cured. Next, the seal portion was completely cured by heating in anoven for one hour at 120° C. In so doing, the various liquid crystaldisplay devices including liquid crystal cells in which the liquidcrystal layer 40 is sealed were completed.

Next, the pre-alignment process compound within the alignment films 22and 32 was reacted by irradiating ultraviolet radiation of 500 mJ(measured at a wavelength of 365 nm) evenly on the liquid crystal cellsproduced in such a manner. In so doing, the alignment films 22 and 32that include the post-alignment process compound were formed on the TFTsubstrate 20 and the CF substrate 30. The liquid crystal display device(liquid crystal display element) with various pretilt angles on theliquid crystal molecules 41A and 41B on the TFT substrate 20 and CFsubstrate 30 side was completed (refer to FIG. 2). Finally, a pair ofpolarization plates was adhered on the outside of the liquid crystaldisplay device so that the absorption axes were orthogonal.

With regard to the liquid crystal display device (liquid crystal displayelement) using such alignment film materials, the response time (startuptime T_(on) and terminal time T_(off) of the image display) and thepretilt angles θ₁ and θ₂ were measured. The results are illustrated inTable 3. Here, “polymer compound 1” in Table 1 was used in Example 1Aand Comparative Example 1A, “polymer compound 2” in Table 1 was used inExample 1B and Comparative Example 1B, and “polymer compound 3” in Table1 was used in Example 1C, Example 1D, and Comparative Example 1D.

When measuring the response time, the time taken to reach a brightnessof 90% of the gradation from a brightness of 10% according to thedriving voltage (startup time T_(on) of the image display) and the timetaken to reach a brightness of 10% of the gradation from a brightness of90% according to the driving voltage (termination time T_(off) of theimage display) were measured by applying a driving voltage (7.5 volts)between the pixel electrodes 20B and the opposing electrodes 30B usingLCD5200 (manufactured by Otsuka Electronics Co., Ltd.) as themeasurement device. Further, when investigating the pretilt angle θ ofthe liquid crystal molecules 41, measurement was performed by a crystalrotation method using a He—Ne laser light complying with a common method(method described in T. J. Scheffer et al., J. Appl. Phys, vol. 19, p.2013, 1980). Here, as described above and illustrated in FIG. 3, thepretilt angle θ is the inclination angle of the directors D of theliquid crystal molecules 41 (41A, 41B) when the driving voltage is in anOFF state in a case when the vertical direction to the surfaces of theglass substrates 20A and 30A (normal vector direction) is Z.

TABLE 3 Rubbing condition First Second Pretilt angle alignment alignmentθ₁ θ₂ T_(off) T_(on) T_(on) + T_(off) film film (degrees) (degrees) (ms)(ms) (ms) Example 1A Condition 1 None 1.3 0 3.02 Condition 2 None 1.8 03.06 Condition 3 None 2.2 0 3.11 Comparative Condition 1 Left 1.3 Left3.76 Example 1A Condition 2 Left 1.8 Left 3.83 Condition 3 Left 2.2 Left4.05 Example 1B Condition 1 None 1.1 0 2.96 Condition 2 None 1.5 0 2.98Condition 3 None 2.0 0 3.06 Comparative Condition 1 Left 1.1 Left 3.66Example 1B Condition 2 Left 1.5 Left 3.72 Condition 3 Left 2.0 Left 3.96Example 1C Condition 1 None 0.8 0 2.82 3.68 6.50 Condition 2 None 1.2 02.99 3.52 6.51 Condition 3 None 1.7 0 2.89 3.25 6.14 ComparativeCondition 1 Left 0.8 Left 3.56 2.83 6.39 Example 1C Condition 2 Left 1.2Left 3.65 2.77 6.42 Condition 3 Left 1.7 Left 3.80 2.78 6.58 Example 1DCondition 1 Condition 1 0.8   0.8 2.96 2.83 5.79 Condition 2 Condition 11.2   0.8 3.04 2.56 5.60 Condition 3 Condition 1 1.7   0.8 3.05 2.425.47

If Example 1A and Comparative Example 1A, Example 1B and ComparativeExample 1B, and Example 1C and Comparative Example 1C are compared,Examples 1A to 1C have a shorter termination time T_(off) thanComparative Examples 1A to 1C. Further, if the total time of the startuptime T_(on) and the termination time T_(off) is compared between Example1C and Comparative Example 1C, there is no great difference. On theother hand, if Example 1D is compared to Example 1C and ComparativeExample 1C, there is an improvement in the total time of the startuptime T_(on) and the termination time T_(off) for Example 1D. Here, thedata from the first row of Example 1D in Table 3 is reference data. Insuch a manner, it is possible to improve the termination time T_(off) bymaking the formation and processing of the second alignment film 32different from the formation and processing of the first alignment film22 and θ₁>θ₂(=0), and furthermore, it is possible to improve the totaltime of the startup time T_(on) and the termination time T_(off) bymaking θ₁>θ₂>0. Here, if overdriving is adopted in Example 1C or Example1D, it is possible to further improve the startup speed T_(on).

As described above, in Example 1 or Example 2 described later, theformation and processing of the first alignment film 22 and the secondalignment film 32 are performed so that the first alignment film 22confers the first pretilt angle θ₁ on the liquid crystal molecules 41Ain the vicinity thereof and the second alignment film 32 confers thesecond pretilt angle θ₂ on the liquid crystal molecules 41B in thevicinity thereof, and the pre-alignment process compound within thealignment films 22 and 32 is cross-linked or polymerized. In so doing,it is possible to greatly improve the response speed (startup speed andtermination speed of the image display).

Example 2

Example 2 relates to the liquid crystal display device (liquid crystaldisplay element) according to the second embodiment of the presentdisclosure and the manufacturing method thereof and the liquid crystaldisplay device (liquid crystal display element) according to the thirdembodiment of the present disclosure and the manufacturing methodthereof. In Example 2, a pretilt is conferred on the liquid crystalmolecules by deforming the polymer compound (pre-alignment processcompound) after sealing the liquid crystal layer. Specifically, the sidechain of the polymer compound (pre-alignment process compound) isdeformed by irradiating ultraviolet radiation while aligning the liquidcrystal molecules by applying a predetermined electric field to theliquid crystal layer. In Example 2, a pre-alignment process compound anda post-alignment process compound including a photosensitive functionalgroup were used. Specifically, a liquid crystal display device with thesame configuration and structure as that described in Example 1 andillustrated in FIG. 2 was produced using the azobenzene compound and thecompound including a styrene skeleton shown in Formulae H-1 and H-2 asthe pre-alignment process compound that includes a photosensitivefunctional group, and the response characteristics were investigated.

In Example 2, the alignment film materials 2A to 2D shown in Table 4were obtained in essence similarly to Example 1. Furthermore, similarlyto Example 1, the formation and processing of alignment films 22 and 32within thicknesses of 90 nm on the pixel electrodes 20B and the opposingelectrodes 30B was performed. Next, similarly to Example 1, a sealportion was formed on the periphery of the pixel portions on the CFsubstrate 30 by applying an ultraviolet curable resin including silicaparticles with a particle diameter of 3.5 μm, and a liquid crystalmaterial composed of MLC-7029 (manufactured by Merck & Co., Inc.) thatis a negative type liquid crystal was poured dropwise into the portionsurrounded by the seal portion. Next, the TFT substrate 20 and the CFsubstrate 30 were adhered together and the seal portion was cured. Next,the seal portion was completely cured by heating in an oven for one hourat 120° C. In so doing, the liquid crystal layer 40 was sealed, and theliquid crystal cells were completed.

TABLE 4 Compound including Compound including Compound includingvertical alignment group able to be photosensitive Diamine inducingstructure along liquid Tetracarboxylic Main chain functional group Firstcompound portion crystal molecules dianhydride spacer that is deformedpolymer Molar Molar Molar Molar Molar Molar compound Material ratioMaterial ratio Material ratio Material ratio Material ratio Materialratio Alignment film A-6 15 B-4 5 E-2 50 G-1 20 H-1 10 material 2AAlignment film A-6 15 B-4 5 E-2 50 G-1 20 H-2 10 material 2B Alignmentfilm A-6 10 C-1 10 E-2 50 G-1 20 H-1 10 material 2C Alignment film B-4 5E-1 50 G-1 20 H-1 25 material 2D

The pre-alignment process compound within the alignment films 22 and 32was then deformed by irradiating ultraviolet radiation of 500 mJ(measured at a wavelength of 365 nm) evenly on the liquid crystal cellsproduced in such a manner. In so doing, the alignment films 22 and 32that include the post-alignment process compound were formed on the TFTsubstrate 20 and the CF substrate 30. The liquid crystal display device(liquid crystal display element) illustrated in FIG. 2 was thuscompleted. Finally, a pair of polarization plates was adhered on theoutside of the liquid crystal display device so that the absorption axeswere orthogonal.

When the response times were measured for liquid crystal display devices(liquid crystal display elements) using such alignment film materials 2Ato 2D, the same results as Example 1 were obtained.

Although the present disclosure has been described above exemplifyingpreferable embodiments and examples, the present disclosure is notlimited to such embodiments, and various modifications are possible. Forexample, although a VA mode liquid crystal display device (liquidcrystal display element) has been described in the embodiments andexamples, the present disclosure is not necessary limited thereto, andis applicable to other display modes such as ECB mode (mode withpositive liquid crystals with horizontal alignment; no twists), IPS (InPlane Switching) mode, FFS (Fringe Field Switching) mode, OCB (OpticallyCompensated Bend) mode, and the like. The same effects are also obtainedin such a case. However, with the embodiments of the present disclosure,compared to not carrying out a pretilt process, with VA mode, it ispossible to exhibit particularly greatly improved effects in theresponse characteristics than IPS mode or FFS mode.

Further, although only a transmission type liquid crystal display device(liquid crystal display element) has been described in the embodimentsand the examples, the present disclosure is not necessarily limited tothe transmission type, and for example, may be a reflection type. In thecase of a reflective type, the pixel electrodes are configured by anelectrode material with light reflectivity such as aluminum.

Although alignment regulating portions were provided only on the firstsubstrate side in the liquid crystal display device described withreference to Embodiment 2, first alignment regulating portions (firstslit portions) may be provided on the first substrate and secondalignment regulating portions (second slit portions) may be provided onthe second substrate. The liquid crystal display device described belowis able to be exemplified as an example of such a liquid crystal displaydevice. That is, a liquid crystal display device is composed of aplurality of pixels being arranged, the liquid crystal display deviceincluding: a first substrate and a second substrate; first electrodesformed on the opposing face of the first substrate that opposes thesecond substrate; first alignment regulating portions provided on thefirst electrodes; a first alignment film that covers the firstelectrodes, the first alignment regulating portions, and the opposingface of the first substrate; second electrodes formed on the opposingface of the second substrate that opposes the first substrate; secondalignment regulation portions that are provided on the secondelectrodes, a second alignment film that covers the second electrodes,the second alignment regulating portions, and the opposing face of thesecond substrate; and a liquid crystal layer that is provided betweenthe first alignment film and the second alignment film and that includesliquid crystal molecules, wherein in each pixel, the long axes of liquidcrystal molecule groups in the liquid crystal layer are approximatelypositioned within the same virtual plane in a central region of anoverlap region in which a projection image of a region surrounded by themargin portions of the first electrodes and the first alignmentregulating portions and a projection image of a region surrounded by themargin portions of the second electrodes and the second alignmentregulating portions overlap, wherein a pretilt is conferred on theliquid crystal molecules by the first alignment film. Here, when thecentral region of the overlap region is viewed from the normal vectordirection of the second substrate, the long axes of the liquid crystalmolecule groups that occupy the central region of the overlap regionalong the normal vector direction of the second substrate (morespecifically, liquid crystal molecule groups that occupy the tinypillar-like region from the first substrate to the second substrate) areapproximately positioned within the same virtual vertical plane.

Here, the second alignment regulating portions are composed of thesecond slit portions that are formed on the second electrodes, the widthof the second slit portions is equal to or greater than 2 μm and lessthan 10 μm, the pitch of the second slit portions is from 10 μm to 180μm, preferably 30 μm to 180 μm, and more preferably 60 μm to 180 μm.

Here, “the central region of the overlap region” refers to a region thata center that matches the center of the overlap region, has a similarshape to the overlap region, and has an area that is 25% of the area ofthe overlap region. Further, “the long axes of the liquid crystalmolecule groups of the liquid crystal layer are approximately positionedwithin the same virtual plane” refers to the angle between the virtualplane and the long axes of the liquid crystal molecule groups beingwithin ±5 degrees. In other words, the variation in the azimuth angles(angles of deviation) of the liquid crystal molecules groups is within±5 degrees. Furthermore, in a case when a pixel is configured by aplurality of subpixels, a pixel may be read as subpixels. Further, atotal reflection damped oscillation method (also known as totalreflection attenuation method) or a phase difference measurement methodis exemplified as a measurement method of the angle between the virtualplane and the long axes of the liquid crystal molecule groups or thevariation in the azimuth angles (angles of deviation) of the liquidcrystal molecule groups. Here, the total reflection damped oscillationmethod is a method of measuring the absorption spectrum of a samplesurface, and by adhering the sample to a high refractive index medium(prism), measures the total reflection of the slight amount of lightthat seeps out from the prism and that is reflected. Furthermore, thetotal reflection damped oscillation method is a method of ascertaininginformation (alignment direction) relating to the absorption ofmolecules around 100 nm (liquid crystals and alignment films) byrotating the orientation of the sample. Further, the phase differencemeasurement method is a method of calculating the pretilt by measuringthe phase difference when the liquid crystal cells are in an inclinedstate by a desired angle using RETS100 (manufactured by OtsukaElectronics Co., Ltd.), calculating the phase difference in the idealalignment state in a state in which a pretilt is conferred in advance,and applying fitting. Further, by rotating the sample within the sampleplane, the azimuth angle at which a pretilt is conferred is able to beascertained.

Schematic partial cross-sectional diagrams of a liquid crystal displaydevice with such a structure are illustrated in FIGS. 17 and 18. Theliquid crystal display device illustrated in FIGS. 17 and 18 is amodification of the liquid crystal display device illustrated in FIGS. 8and 9.

A plurality of pixel electrodes 20B are arranged in a matrix shape, forexample, on the surface of the side that opposes the CF substrate 30composed of a glass substrate on the TFT substrate 20 composed of aglass substrate. Furthermore, TFT switching elements provided withgates, sources, drains, and the like that respectively drive theplurality of pixel electrodes 20B, gate lines and source lines that areconnected to such TFT elements, and the like (not shown) are provided. Apixel electrode 20B is provided for every pixel that is electricallyseparated by a pixel separation portion 52, and for example, isconfigured by a material with transparency such as ITO (indium tinoxide). First slit portions 21 (portion on which an electrode is notformed) with a striped or V-shaped pattern, for example, are providedwithin each pixel on the pixel electrodes 20B. In so doing, when adriving voltage is applied, since an electric field that is diagonalwith respect to the long axis direction of the liquid crystal molecules41 is conferred and regions with different alignment directions areformed within the pixels (alignment demarcation), the viewing anglecharacteristics are improved. That is, the first slit portions 21 arethe first alignment regulating portions for regulating the entirety ofthe liquid crystal molecules 41 within the liquid crystal layer 40 forsecuring favorable display characteristics, and here, the alignmentdirection of the liquid crystal molecules 41 when a driving voltage isapplied is regulated by the first slit portions 21. As described above,in essence, the azimuth angle of the liquid crystal molecules when apretilt is conferred is regulated by the strength and direction of theelectric field and the molecular structure of the alignment filmmaterial, and the direction of the electric field is determined by thealignment regulating portions.

On the CF substrate 30, color filters (not shown) that are configured,for example, by red (R), green (G), and blue (B) striped filters and theopposing electrodes 30B are arranged on approximately the entirety ofthe effective display region on the opposing face with the TFT substrate20. Similarly to the pixel electrodes 20B, the opposing electrodes 30Bare configured by a material with transparency such as, for example,ITO. Similarly to the pixel electrodes 20B, second slit portions 31(portion on which an electrode is not formed) with a striped or V-shapedpattern, for example, are provided within each pixel of the opposingelectrodes 30B. In so doing, when a driving voltage is applied, since anelectric field that is diagonal with respect to the long axis directionof the liquid crystal molecules 41 is conferred and regions withdifferent alignment directions are formed within the pixels (alignmentdemarcation), the viewing angle characteristics are improved. That is,the second slit portions 31 are the second alignment regulating portionsfor regulating the entirety of the liquid crystal molecules 41 withinthe liquid crystal layer 40 for securing favorable displaycharacteristics, and here, the alignment direction of the liquid crystalmolecules 41 when a driving voltage is applied is regulated by thesecond slit portions 31. As described above, in essence, the azimuthangle of the liquid crystal molecules when a pretilt is conferred isregulated by the strength and direction of the electric field and themolecular structure of the alignment film material, and the direction ofthe electric field is determined by the alignment regulating portions.

The second slit portions 31 are arranged so as to not oppose the firstslit portions 21 between the substrates. More specifically, a pluralityof first slit portions 21 are provided to be parallel to one another,and a plurality of second slit portions 31 are also provided to beparallel to one another. Further, a plurality of first slit portions 21extend in two directions that are orthogonal to each other within apixel, and similarly, a plurality of second slit portions 31 extend intwo directions that are orthogonal to each other. Furthermore, the firstslit portions 21 are provided to be parallel to the second slit portions31 that oppose the first slit portions 21, and the projection image of afirst slit portion 21 is positioned over the projection image on a lineof symmetry of two second slit portions 31, and the projection image ofa second slit portion 31 is positioned over the projection image on aline of symmetry of two first slit portions 21. An arrangement diagramof the first electrodes (pixel electrodes) 20B and the first slitportions 21, and the second electrodes (opposing electrodes) 30B and thesecond slit portions 31 when viewed from above is illustrated in FIG.19A, and an arrangement diagram of the second electrodes (opposingelectrodes) 30B and the second slit portions 31 is illustrated in FIG.19B. Further, a modification of the outer shapes of the first slitportions 21 and the second slit portions 31 is illustrated in FIGS. 20Aand 20B and FIGS. 21A and 21B. Here, in FIGS. 19A, 20A, and 21A, themargin portions of the first electrode (pixel electrode) 20B and thefirst alignment regulating portions (first slit portions 21) areillustrated by solid lines, and the second alignment regulating portions(second slit portions 31) positioned thereabove are illustrated bydotted lines. Further, diagonal shading is given to the overlap region50 in which the projection image of the region surrounded by the marginportion of the first electrode (pixel electrode) 20B and the firstalignment regulating portions (first slit portions 21) and theprojection image of the region surrounded by the margin portion of thesecond electrode (opposing electrode) 30B and the second alignmentregulating portions (second slit portions 31) overlap, and furthermore,the central region 51 is surrounded by a broken chain line with diagonalshading. For convenience, only one overlap region 50 and central region51 is shown. Further, in FIGS. 19B, 20B, and 21B, the margin portions ofthe second electrode (opposing electrode) 30B and the second alignmentregulating portions (second slit portions 31) are illustrated by solidlines. Here, the shape of the first alignment regulating portions (firstslit portions 21) may be substituted by the shape of the secondalignment regulating portions (second slit portions 31), and the shapeof the second alignment regulating portions (second slit portions 31)and the shape of the first alignment regulating portions (first slitportions 21) may be substituted.

Furthermore, in each pixel (subpixel), in the central region 51 of theoverlap region 50 in which the projection image of the region surroundedby the margin portions of the first electrodes (pixel electrodes) 20Band the first alignment regulating portions (first slit portions 21) andthe projection image of the region surrounded by the margin portions ofthe second electrodes (opposing electrodes) 30B and the second alignmentregulating portions (second slit portions 31) overlap, the long axes ofthe liquid crystal molecule groups in the liquid crystal layer 40 arepositioned approximately within the same virtual plane. That is, thevariation in the azimuth angles (angles of deviation) of the liquidcrystal molecule groups in the liquid crystal layer 40 is within ±5degrees.

With such a liquid crystal display device, since the first slit portions21 and the second slit portions 31 are provided on the TFT substrate 20and the CF substrate 30 as alignment regulating portions for regulatingthe alignment of the liquid crystal molecules 41 and displaycharacteristics such as the viewing angle characteristics are secured,the response characteristics are improved in a state in which favorabledisplay characteristics are maintained. Moreover, in the central region51 of the overlap region 50, the liquid crystal molecules groups in theliquid crystal layer 40 are not in a twisted state. There is thereforeno time taken in untwisting the twists in the long axes of the liquidcrystal molecule groups when a voltage is applied to a pair ofelectrodes 20B and 30B, further improving the response characteristics.Here, the state of the twists in the long axes of the liquid crystalmolecule groups is schematically illustrated in FIGS. 22A and 22B. Here,the liquid crystal molecules 41B illustrated at the top of FIGS. 22A and22B indicate liquid crystal molecules that are positioned in thevicinity of the first substrate, the liquid crystal molecules 41Aillustrated at the bottom of FIGS. 22A and 22B indicate liquid crystalmolecules that are positioned in the vicinity of the first substrate,and the liquid crystal molecules 41C illustrated in the middle of FIGS.22A and 22B illustrate liquid crystal molecules that are positionedbetween the first substrate and the second substrate. Further, thedotted lines that cross the liquid crystal molecules illustrate the longaxes of the liquid crystal molecules. In the state illustrated in FIG.22A, the liquid crystal molecule groups in the liquid crystal layer 40are not in a twisted state. On the other hand, in the state illustratedin FIG. 22B, the liquid crystal molecule groups in the liquid crystallayer 40 are in a twisted state.

In a central region of an overlap region in which the projection imageof the region surrounded by the margin portions of the first electrodes20B and the first alignment regulating portions and the projection imageof the region surrounded by the margin portions of the second electrodes30B and the second alignment regulating portions overlap, the long axesof the liquid crystal molecule groups in the liquid crystal layer arepositioned approximately within the same virtual plane. In other words,the variation in the azimuth angles (angles of deviation) of the liquidcrystal molecule groups in the liquid crystal layer is within ±5degrees. In such a manner, in the central region of the overlap region,the liquid crystal molecule groups in the liquid crystal layer do nothave the long axes of the liquid crystal molecule groups in a twistedstate from one electrode side toward the other electrode side. Sincethere is therefore no time taken in untwisting the twists in the longaxes of the liquid crystal molecule groups when a voltage is applied toa pair of electrodes and a response is possible within the same plane,the response characteristics are able to be improved further.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2011-040326 filed in theJapan Patent Office on Feb. 25, 2011, the entire contents of which arehereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A liquid crystal display device comprising: afirst alignment film and a second alignment film that are provided onopposing face sides of a pair of substrates and a liquid crystal layerthat is provided between the first alignment film and the secondalignment film, wherein the first alignment film includes a compound inwhich a polymer compound that includes a cross-linked functional groupor a polymerized functional group as a side chain is cross-linked orpolymerized, the second alignment film includes a same compound as thecompound that configures the first alignment film, and a pretilt angleof the liquid crystal molecules which is conferred by the firstalignment film is greater than a pretilt angle of the liquid crystalmolecules which is conferred by the second alignment film.
 2. The liquidcrystal display device according to claim 1, wherein a formation andprocessing of the second alignment film is different from a formationand processing of the first alignment film.
 3. The liquid crystaldisplay device according to claim 1, wherein the formation andprocessing of the first alignment film includes a rubbing process, theformation and processing of the second alignment film includes a rubbingprocess, and rubbing process conditions for the second alignment filmare different from rubbing process conditions for the first alignmentfilm.
 4. A liquid crystal display device comprising: a first alignmentfilm and a second alignment film that are provided on opposing facesides of a pair of substrates and a liquid crystal layer that isprovided between the first alignment film and the second alignment film,wherein the first alignment film includes a compound in which a polymercompound that includes a photosensitive functional group as a side chainis deformed, the second alignment film includes a same compound as thecompound that configures the first alignment film, and a pretilt angleof the liquid crystal molecules which is conferred by the firstalignment film is greater than a pretilt angle of the liquid crystalmolecules which is conferred by the second alignment film.
 5. The liquidcrystal display device according to claim 4, wherein a formation andprocessing of the second alignment film is different from a formationand processing of the first alignment film.
 6. A manufacturing method ofa liquid crystal display device comprising: performing formation andprocessing of a first alignment film composed of a polymer compound thatincludes a cross-linked functional group or a polymerized functionalgroup as a side chain on one of a pair of substrates and performingformation and processing of a second alignment film composed of a samepolymer compound as the polymer compound that configures the firstalignment film on the other of the pair of substrates; arranging thepair of substrates so that the first alignment film and the secondalignment film are opposing and sealing a liquid crystal layer betweenthe first alignment film and the second alignment film; and conferring apretilt on the liquid crystal molecules by cross-linking or polymerizingthe polymer compound, wherein the formation and processing of the secondalignment film is different from the formation and processing of thefirst alignment film.
 7. The manufacturing method of the liquid crystaldisplay device according to claim 6, wherein a pretilt angle of theliquid crystal molecules which is conferred by the first alignment filmis greater than a pretilt angle of the liquid crystal molecules which isconferred by the second alignment film.
 8. The manufacturing method ofthe liquid crystal display device according to claim 6, wherein theformation and processing of the first and second alignment film includea process for irradiating the polymer compound with energy rays or aprocess for heating the polymer compound while aligning the liquidcrystal molecules by applying a predetermined electric field on theliquid crystal layer.
 9. The manufacturing method of the liquid crystaldisplay device according to claim 8, wherein the formation andprocessing of the second alignment film is different from the formationand processing of the first alignment film in a heating processcondition.
 10. The manufacturing method of the liquid crystal displaydevice according to claim 6, wherein the formation and processing of thefirst alignment film includes a rubbing process, the formation andprocessing of the second alignment film includes a rubbing process, andrubbing process conditions for the second alignment film are differentfrom rubbing process conditions for the first alignment film.
 11. Amanufacturing method of a liquid crystal display device comprising:performing formation and processing of a first alignment film composedof a polymer compound that includes a photosensitive functional group asa side chain on one of a pair of substrates and performing formation andprocessing of a second alignment film composed of a same polymercompound as the polymer compound that configures the first alignmentfilm on the other of the pair of substrates; arranging the pair ofsubstrates so that the first alignment film and the second alignmentfilm are opposing and sealing a liquid crystal layer between the firstalignment film and the second alignment film; and conferring a pretilton the liquid crystal molecules by deforming the polymer compound,wherein the formation and processing of the second alignment film isdifferent from the formation and processing of the first alignment film.12. The manufacturing method of the liquid crystal display deviceaccording to claim 11, wherein a pretilt angle of the liquid crystalmolecules which is conferred by the first alignment film is greater thana pretilt angle of the liquid crystal molecules which is conferred bythe second alignment film.
 13. The manufacturing method of the liquidcrystal display device according to claim 11, wherein the formation andprocessing of the first and second alignment film include a process forirradiating the polymer compound with energy rays or a process forheating the polymer compound while aligning the liquid crystal moleculesby applying a predetermined electric field on the liquid crystal layer.14. The manufacturing method of the liquid crystal display deviceaccording to claim 13, wherein the formation and processing of thesecond alignment film is different from the formation and processing ofthe first alignment film in a heating process condition.
 15. Amanufacturing method of a liquid crystal display device comprising:performing formation and processing of a first alignment film composedof a polymer compound that includes a cross-linked functional group or aphotosensitive functional group as a side chain on one of a pair ofsubstrates and performing formation and processing of a second alignmentfilm composed of a same polymer compound as the polymer compound thatconfigures the first alignment film on the other of the pair ofsubstrates; arranging the pair of substrates so that the first alignmentfilm and the second alignment film are opposing and sealing a liquidcrystal layer between the first alignment film and the second alignmentfilm; and conferring a pretilt on the liquid crystal molecules byirradiating the polymer compound with energy rays, wherein the formationand processing of the second alignment film is different from theformation and processing of the first alignment film.
 16. Themanufacturing method of the liquid crystal display device according toclaim 15, wherein a pretilt angle of the liquid crystal molecules whichis conferred by the first alignment film is greater than a pretilt angleof the liquid crystal molecules which is conferred by the secondalignment film.